Nt1310 Unit 1 Assignment
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AUTHENTICATION DECLARATION
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If I have used another person’s work, it has been distinguished from my own work through:
The use of quotation marks within …show more content…
a paragraph, or
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I have referenced these sources within the text, and provided full descriptions in the bibliography.
I have read, understood and followed the College’s Statement on Plagiarism and the Course Handbook for this piece of work.
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Unit 13: Physiology of Fluid Balance
P1: Describe the microstructure of a typical animal cell and the functions of the main cell components.
P2: Explain the ways in which materials move in and out of the cells.
M1: Explain factors that influence the movement of materials into and out of cells.
D1: Analyse the role of phospholipid bilayer in terms of the movement of materials into and out of cells.
In this assignment I will be describing the microstructure of a typical animal cell and the functions of the main cell components, I will be explaining the ways in which materials move in and out of the cells, also the factors that influence the movement of materials into and out of cells. I will also be analysing the role of phospholipid bilayer in terms of the movement of materials into and out of cells.
Cells are the basic unit of living material; it is the smallest structural unit in an organism which can function independently. Cells all have different sizes, shapes, and jobs to do. Your body is made up of around 200 different types of cell, all working together, day and night. Each cell must make the molecules it needs to survive, grow, multiply and do its job. In our body we have 100 million cells, of 200 different types, however length of cells live can be different;
White blood cells only live for 13 days
Red blood cells live for about 120days
Liver cells live about 18months
Nerve cells can live up to 100years
Most of the cells in our body are made up of water, the rest are a mixture of molecules, mainly protein, lipids, and carbohydrates. All the cells are different because they come in all different shapes and sizes, they make different proteins according to the jobs they have to do. For example, only red blood cells contain the protein haemoglobin which carries oxygen around your body.
In our body all cells are different they all come in all shapes and sizes. They are different because each different types of cell make different proteins according to the job they have to do. For example, only red blood cells contain the protein haemoglobin which carries oxygen around your body. Similarly, only cells in your eyes make proteins for detecting light, As well as these ‘specialised’ proteins, almost all your cells share a common set of ‘housekeeping’ proteins.
Each of our cells is like a tiny factory, inside thousands of chemical reactions take place every day in separate compartments. In the middle of the cell is the nucleus, the ‘manager’s office.’ This contains a copy of your genes, the instructions for making proteins. Inside other compartments, the cell generates power, gets rid of waste, and makes molecules it needs to survive, work and grow.
This is a picture of inside a cell;
Nucleus and cell membrane (as a phospholipid bilayer) – The Nucleus is the most important thing in a cell, it is the control centre for the cell which means it controls what it looks like and what it does, it contains DNA. Cells are bounded by their cells or plasma membranes. These membranes have the same biochemical structure. The membranes are composed of a double layer of phospholipid molecules, proteins, cholesterol and, sometimes, sugars. The phospholipid bilayer is interrupted at intervals known as nuclear pores, this then provides for communication between the nucleus and cytoplasm inside the nucleus is called neoplasm. Which contains the chromatin network composed of DNA and proteins, inside the nucleus there is also found RNA, which is linked to controlling chemical activities taking place inside the cell.
Phospholipid Bilayer – This is composed of proteins, cholesterol and sugars. The top of the phospholipid bilayer is made of glycerol, phosphorus and nitrogen atoms and the green bottom are made from chains of fatty acids. The electrically charged head, known as the polar head are hydrophilic as it exists against water molecules, whereas the fatty acids dislike water and are known as hydrophobic.
Cholesterol molecules are inserted into the bilayer at intervals and these tend to help stabilise the freely moving bilayer, which acts rather like a fluid itself. Various sugar chains may add to phospholipid (glycolipid) or proteins (glycoproteins) may enable cells to stick together to form tissues and act as identity markers or receptor sites for hormones, enzymes etc.
Nucleus and chromosomes – The nucleus is limited by the nuclear membrane, which is a phospholipid bilayer interrupted at intervals, which is known nuclear pores. These provide direct communication between the cytoplasm and nucleus. The soft material inside the nucleus is called nucleoplasm which has no particular features.
DNA – DNA is the short for Deoxyribonucleic Acid, which is responsible for transmitting inherited characteristics. DNA in found inside the nucleus is it the control centre for the cell, it contains information that tells the cell how to make different proteins. Which then the nucleus can therefore control what the cell looks like and what is does. DNA is made up of nucleotides which consist of a base, a sugar and phosphate grouping. There are 4 different bases, adenine, guanine, cytosine and thymine. The bases always combine in the same way, adenine and thymine together and guaine and cytosine. So A and T and G and C for chemical ‘rungs’, with the sugar and phosphate molecules forming the sides of the ladder.
Nucleotides – Is a strand of DNA which is known as a double helix. The bases always combine in the same way, adenosine to thymine and guanine to cytosine. The bases form the rungs with the sugar and phosphate molecules forming the sides of the ladder, with the bases held together by hydrogen bonds.
RNA – DNA never leaves the nucleus, so an intermediary must carry messages for the production of enzymes and proteins. DNA unwinds and splits, one strand forming messenger RNA, which then ‘zips’ back up into a double helix. This process is known as transcription. These are molecules that convey genetic information from DNA to the ribosome, where they specify the amino acid sequence of the protein products of gene expression. Ribosomes are made up from ribosomal RNA. Ribosomes attach themselves to the mRNA strand and they begin the process of converting the code into an amino acid sequence. This process is known as translation. Another type of RNA carries amino acids to the ribosomes to be formed into a protein chain. This process is called transfer RNA.
Ribosomes – This interpret cellular information from the nucleus so it produce appropriate proteins, they float freely in the cytoplasm or sometimes bind to another organelle called endoplasmic reticulum. They contain 65% RNA and exist in large numbers in cells producing proteins for export, e.g. the pancreas. They are made up of another type or RNA, called ribosomal RNA (or rRNA for short). Ribosomes become attached to the mRNA strand and the process of converting the code into sequences of amino acids begins. This process is known as translation.
tRNA – Two tRNA molecules with their amino acids can attach to a ribosomes at the same time and a peptide bond will form between them; the ribosomes then rolls on the mRNA and third and fourth amino acids are added, each forming a peptide bond with the next in the chain, and so on.
All types of RNA are made by transcription of a relevant section (gene) of DNA in the nucleus.
Endoplasmic Reticulum– A series of membranes folded to form channels. The ribosomes are attached to the membranes, it is these membrane channels that proteins are made. These are two forms rough and smooth. Much of the endoplasmic reticulum has a rough appearance because it is studded with tiny black bodies known as ribosomes, this is known as the rough endoplasmic reticulum. The part of membranous sacs do not carry ribosomes and this is known as smooth endoplasmic reticulum.
Golgi apparatus – These collect protein from the endoplasmic reticulum and package and modify it before it is used of excreted from the cell.
Mitochondria – mitochondria are round or sausage-shaped bodies found in large numbers (100plus) in the cytoplasm. The cell has double layers and the inner layer is folded to form internal shelves called cristae. When the food is broken down in aerobic respiration it releases energy for use by the cell. Enzymes that catalyse the breakdown of glucose are dissolved in the internal fluid, while enzymes for the formation of ATP lie on the cristae.
Lysosomes – A function of a lysosome is to digest foreign bacteria that invade a cell and any other unwanted materials such as old organelles. These contain enzymes that aid in the digestion of nutrient molecules and other materials. Whole cell can also be destroyed in this was, a process called autolysis.
Vaculoes may store food or any variety of nutrients a cell might need to survive. They also store waste so that the cell is free from contamination.
Other microstructures including centrioles and cilia, exist in some cells or in most cells at particular times.
Centrioles which are the two tiny hallow cylinders close to the nucleas. They contain microtubles, which can replicate themselves. They do this at the time beginning of cell division, moving to opposite sides of the cell. A spindle of microtubles is formed between them, they help to conrol the separation of the chromosomes to form two new cells.
Cilia these protrude from the cell surface next to mucus secreting cells. They beat to effect transport of the mucus and other materials. The base of a cilium has the same microtubular as the centrioles and is believed to be formed from them.
Functions of the main cells components
Cell Membrane – This is important because it protects the cell with semi-permeable which controls the movement of water, nutrients and waste in and out of the cell. The cell membrane and nucleus are both bound by a phospholipid bilayer. The cell membrane act as a selective barrier to substances entering and leaving the cell. It holds certain receptors sites to which other molecules, such as hormones, can attach. Its function is to also contribute to immunological identity of the cell. It interacts with the surroundings environment, and with adjacent cells. Due to the fluid of the membrane, ‘holes’ or damage can be repaired almost instantaneously.
Nuclear membrane – Acts as a selective barrier to substances entering and leaving the nucleus. Nuclear pores allow communication between the Endoplasmic Reticulum and the nucleus. The nuclear membrane also defines the boundary of genetic material such as DNA.
Nucleus – This controls the cellular activities. It contains chromosomes and thus genetic information. It’s the site of transcription of mRNA from DNA. Ultimately responsible for protein production in the ribosomes. Nuclear division precedes cell division.
Chromosome – This carries theoretical units of inheritance called genes. It contains DNA that is responsible for controlling the protein production. Capable of replication prior to cell division.
Endoplasmic reticulum – Forms an internal cellular transport system.
It enables communication between the cell membrane, the nucleus and the environment. Carries ribosomes that are responsible for the production of proteins (rough). Synthesis lipids from fatty acids and glycerol and transports these to the Golgi body (smooth).
Ribosomes – This binds to the rough endoplasmic reticulum and to the mRNA. It also enables translation of mRNA to produce proteins.
Golgi apparatus – Receives proteins from the ribosomes via endoplasmic reticulum and chemically modifies them for export (particularly in secreting cells). Produces vesicles to transport the modified proteins to the cell membrane for release. It receives and modifies lipids from the smooth endoplasmic reticulum for transport to the cell membrane. It also produces lysosomes containing digestive enzymes.
Mitochondria – complete the oxidation of glucose to release energy. It traps the energy released to form ATP, which is used to power the metabolic functions of the cells.
Cilia – this transports mucus and other materials that may stuck in them to the exterior by continuous rhythmic …show more content…
beating.
There are many materials found in the body moving in and out of cells. The cells are continously needing to take in material from their surroundings and, conversly, exporting or eliminating materials to their surroundings.
States of matter – Matter is the material which has substances and occupies space. Solids, Liquids, and gases are called the three states of matter that must be distinguished. All of these are made from atoms which are the smallest parts and can take part in chemical reactions and molecules which are composed of more than one atom. These atoms are made from smaller particles known as protons and electrons.
Particulate material - Particles such as coal dust, asbestos, carbon etc. is very fine and can cause scarring on tiny air passage ways, enter open wounds where macrophages will need to engulf and digest them.
Ironic material – This material containing atoms that may have a positive or negative charge as a result of gaining or losing electrons. These atoms are called irons or electrolytes. Ionic materials is designated by the relevant charge shown against the atom, e.g. Na+, K+, Cl+.
In solution – substances that are capable of dissolving in a liquid are called solutes. Water is the most common molecule in the human body and most chemicals reactions involve molecules dissolved in water.
Water – water is composed of two hydrogen atoms linked by chemical bonds to one oxygen atom. The hydrogen atoms have a slight positive charges and the oxygen a slight negative charge, so water exists as a polar molecules.
Colloidal forms -
Protein sols – Cytoplasm and blood plasma are both examples of colloid because they are not readily dissolved in water so it classes as protein sol.
Emulsions - An emulsion occurs when one liquid is dispersed in droplets in another, such as fat in milk. This is what happens when bile salts are added to fats in chime; the fat break down into thousands of globules.
Diffusion – Molecules, atoms and irons are in constant motion, more so in liquids and gases, as they are further apart. When there is a large numbers of molecules of a substance and a small number in another area, with no barrier between them, this motion will cause the numbers to even up, which is known as diffusion.
Concentration Gradient - Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. Each are has a different concentration which is known as a concentration gradient. The greater the concentration gradient the faster the rate of diffusion. As the numbers of molecules become more evenly spread the movement of down molecules will eventually slow down and stop. This is termed a state of equilibrium.
Diffusion in the body – In the body, diffusion often takes place through cell membranes. In the lungs there are only two simple squamous epithelial cells separating the gases in the alveoli from the blood in the pulmonary capillaries. No energy is needed for diffusion.
Facilitated Diffusion – Some material diffuse through the cell membrane by a related process known as facilitated diffusion. To facilitate something means to make it easier and the protein channel in the cell membrane assist in transporting molecules into and out of the cells. The concentration gradient is important, as is the number of protein channels available. The channels have a special receptor which changes shape to prevent other molecules from entering until the first molecule has reached the other side. Facilitated diffusion is particularly important in the transport of glucose into the cells, as cells are normally impermeable to glucose.
Osmosis – Osmosis is a special type of diffusion of water molecules. It is the movement of water molecules from an area of high concentration to an area of low concentration through a selectively permeable membrane. The concentration gradient is only concerned with number of water molecules.
Active Transport - Sometimes material passes through cells against a concentration gradient; neither diffusion nor osmosis can account for this. This is active transport. The process is powered by the release of energy from ATP in the cells. The digestion of carbohydrate in the intestine produces glucose and this requires active transport across villi cells against a concentration gradient.
Endocytosis – This is the process of taking materials that are outside the cell into the cell phagocytosis (cell eating) or pinocytosis (cell drinking). Pinocytosis occurs in all cells, but phagocytosis only occurs in special cells such as white blood cells. Endocytosis requires energy from ATP to complete the task.
Exocytosis - This means the process of releasing materials from the cell into the tissue fluid. This method is used for molecules that cannot pass through the cell membrane by diffusion or osmosis.
There are many influences on why materials move in and out of cells. Important factors for diffusion and osmosis include the availability of energy from ATP and the fluidity of cell membranes. The surface area and thickness of selectively permeable membranes will also affect the rates of diffusion and osmosis.
Size - Some molecules are too big to move through a selectively permeable membrane.
The size of the surface must also be large enough to allow sufficient molecules to be transported to accommodate the metabolic processes in cell. For this reason, the surface area to volume ratio for any cell is critical. Size is also important in terms of width and length of a surface carrying out transport of materials. For example; the surface area of single-called alveoli in a person’s lungs, if spread out flat on a surface, would total the area of a football pitch.
Distance – Distance is the same as size, any disease that affects the distance reduces the transportation process. For example; dissolves gases such as oxygen and carbon dioxide pass across the alveolar/capillary interface with ease in a healthy person. A person with pneumonia has extra fluid in the alveoli, resulting in slower gaseous exchange and therefore a lack of oxygen. Diffusion can distribute molecules quickly over a short distance but is very slow over more than a few centimetres.
Temperature – Increasing temperature will also increase kinetic energy, therefore molecules will move faster in diffusion and osmosis. The average speed of molecules depends on temperature and the mass of
molecules.
Concentration gradient – The concentration on each region must be different and this is known as a concentration gradient. The greater the concentration gradient, the faster the rate of diffusion.
Osmotic potential – This is power of a solution to gain or lose water molecules through a membrane. Weaker or more dilute solutions have higher osmotic potentials than concentrated solutions; it follows therefore that pure water has the highest osmotic potential.
Electrochemical gradient – Cells have a difference in electrical charge across the cell membrane, the exterior of the cell membrane carrying positive charges and the interior negative charges. This is called a membrane potential which affects the diffusion of ions across the membrane. The result of this is that positively charged ions will be attracted into the cell and negatively charged ions will be repelled. This operates even where there is no concentration gradient which is referred as electrochemical gradient.
Permeability of cell membrane – some charged or polar molecules and ions diffuse across the phospholipid bilayer very slowly, or not at all. Whereas non-polar molecules diffuse faster. This is because they dissolve in the fatty acid chains or the lipid layer of the cell membrane. Materials such as dissolved oxygen, carbon dioxide, fatty acids, and steroid muscles diffuse in this way quite easily and rapidly.
Channel proteins - Experiments have shown that an artificial bilayer membrane containing no protein results in virtual impermeability to ions such sodium, potassium, chloride and calcium. This suggests that the protein channels are responsible for the permeability of the cell membrane to polar ions and molecules. Shapes of membrane protein channels are varied and related to the ions they allow though. The channels are very small so preventing other molecules from passing.
Carrier molecules – There are many types of carrier molecules in membranes, each specific to a particular substance or group of substances by way of its characteristic binding sites. For example, amino acids and sugars have different binding sites and carrier proteins.
In this assignment I have learnt the various types of cells in a typical animal cell and their functions, also their materials that move in and out of the cells, also what the phospholipid bilayer is and the movement of material into and out of the cell.
Bibliography
Health and social care book level 3
http://en.wikipedia.org/wiki/Lipid_bilayer http://en.wikipedia.org/wiki/Endoplasmic_reticulum http://en.wikipedia.org/wiki/Diffusion
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/cells/cells3.shtml
Work will not be marked unless accompanied by a completed submission form. Thank you.
Surname:
First Name:
Learner ID Number:
Programme
Teacher/Assessor:
Assessment Title
Unit Numbers:
AUTHENTICATION DECLARATION
This submission is my own work.
I have made no use of printed, electronic or oral sources, apart from those which have been openly and fully acknowledged in this piece of coursework.
If I have used another person’s work, it has been distinguished from my own work through:
The use of quotation marks within …show more content…
a paragraph, or
A separate indented paragraph (for larger quotes)
I have referenced these sources within the text, and provided full descriptions in the bibliography.
I have read, understood and followed the College’s Statement on Plagiarism and the Course Handbook for this piece of work.
SIGNED: _________________________________________________________________
ASSESSMENT ACKNOWLEDGEMENT FORM
(To be completed by receiver and returned to learner for their records)
Assessment Title:
Name Of Receiver:
Job Title:
Contact Ext No.:
Date Assessment Received
Unit 13: Physiology of Fluid Balance
P1: Describe the microstructure of a typical animal cell and the functions of the main cell components.
P2: Explain the ways in which materials move in and out of the cells.
M1: Explain factors that influence the movement of materials into and out of cells.
D1: Analyse the role of phospholipid bilayer in terms of the movement of materials into and out of cells.
In this assignment I will be describing the microstructure of a typical animal cell and the functions of the main cell components, I will be explaining the ways in which materials move in and out of the cells, also the factors that influence the movement of materials into and out of cells. I will also be analysing the role of phospholipid bilayer in terms of the movement of materials into and out of cells.
Cells are the basic unit of living material; it is the smallest structural unit in an organism which can function independently. Cells all have different sizes, shapes, and jobs to do. Your body is made up of around 200 different types of cell, all working together, day and night. Each cell must make the molecules it needs to survive, grow, multiply and do its job. In our body we have 100 million cells, of 200 different types, however length of cells live can be different;
White blood cells only live for 13 days
Red blood cells live for about 120days
Liver cells live about 18months
Nerve cells can live up to 100years
Most of the cells in our body are made up of water, the rest are a mixture of molecules, mainly protein, lipids, and carbohydrates. All the cells are different because they come in all different shapes and sizes, they make different proteins according to the jobs they have to do. For example, only red blood cells contain the protein haemoglobin which carries oxygen around your body.
In our body all cells are different they all come in all shapes and sizes. They are different because each different types of cell make different proteins according to the job they have to do. For example, only red blood cells contain the protein haemoglobin which carries oxygen around your body. Similarly, only cells in your eyes make proteins for detecting light, As well as these ‘specialised’ proteins, almost all your cells share a common set of ‘housekeeping’ proteins.
Each of our cells is like a tiny factory, inside thousands of chemical reactions take place every day in separate compartments. In the middle of the cell is the nucleus, the ‘manager’s office.’ This contains a copy of your genes, the instructions for making proteins. Inside other compartments, the cell generates power, gets rid of waste, and makes molecules it needs to survive, work and grow.
This is a picture of inside a cell;
Nucleus and cell membrane (as a phospholipid bilayer) – The Nucleus is the most important thing in a cell, it is the control centre for the cell which means it controls what it looks like and what it does, it contains DNA. Cells are bounded by their cells or plasma membranes. These membranes have the same biochemical structure. The membranes are composed of a double layer of phospholipid molecules, proteins, cholesterol and, sometimes, sugars. The phospholipid bilayer is interrupted at intervals known as nuclear pores, this then provides for communication between the nucleus and cytoplasm inside the nucleus is called neoplasm. Which contains the chromatin network composed of DNA and proteins, inside the nucleus there is also found RNA, which is linked to controlling chemical activities taking place inside the cell.
Phospholipid Bilayer – This is composed of proteins, cholesterol and sugars. The top of the phospholipid bilayer is made of glycerol, phosphorus and nitrogen atoms and the green bottom are made from chains of fatty acids. The electrically charged head, known as the polar head are hydrophilic as it exists against water molecules, whereas the fatty acids dislike water and are known as hydrophobic.
Cholesterol molecules are inserted into the bilayer at intervals and these tend to help stabilise the freely moving bilayer, which acts rather like a fluid itself. Various sugar chains may add to phospholipid (glycolipid) or proteins (glycoproteins) may enable cells to stick together to form tissues and act as identity markers or receptor sites for hormones, enzymes etc.
Nucleus and chromosomes – The nucleus is limited by the nuclear membrane, which is a phospholipid bilayer interrupted at intervals, which is known nuclear pores. These provide direct communication between the cytoplasm and nucleus. The soft material inside the nucleus is called nucleoplasm which has no particular features.
DNA – DNA is the short for Deoxyribonucleic Acid, which is responsible for transmitting inherited characteristics. DNA in found inside the nucleus is it the control centre for the cell, it contains information that tells the cell how to make different proteins. Which then the nucleus can therefore control what the cell looks like and what is does. DNA is made up of nucleotides which consist of a base, a sugar and phosphate grouping. There are 4 different bases, adenine, guanine, cytosine and thymine. The bases always combine in the same way, adenine and thymine together and guaine and cytosine. So A and T and G and C for chemical ‘rungs’, with the sugar and phosphate molecules forming the sides of the ladder.
Nucleotides – Is a strand of DNA which is known as a double helix. The bases always combine in the same way, adenosine to thymine and guanine to cytosine. The bases form the rungs with the sugar and phosphate molecules forming the sides of the ladder, with the bases held together by hydrogen bonds.
RNA – DNA never leaves the nucleus, so an intermediary must carry messages for the production of enzymes and proteins. DNA unwinds and splits, one strand forming messenger RNA, which then ‘zips’ back up into a double helix. This process is known as transcription. These are molecules that convey genetic information from DNA to the ribosome, where they specify the amino acid sequence of the protein products of gene expression. Ribosomes are made up from ribosomal RNA. Ribosomes attach themselves to the mRNA strand and they begin the process of converting the code into an amino acid sequence. This process is known as translation. Another type of RNA carries amino acids to the ribosomes to be formed into a protein chain. This process is called transfer RNA.
Ribosomes – This interpret cellular information from the nucleus so it produce appropriate proteins, they float freely in the cytoplasm or sometimes bind to another organelle called endoplasmic reticulum. They contain 65% RNA and exist in large numbers in cells producing proteins for export, e.g. the pancreas. They are made up of another type or RNA, called ribosomal RNA (or rRNA for short). Ribosomes become attached to the mRNA strand and the process of converting the code into sequences of amino acids begins. This process is known as translation.
tRNA – Two tRNA molecules with their amino acids can attach to a ribosomes at the same time and a peptide bond will form between them; the ribosomes then rolls on the mRNA and third and fourth amino acids are added, each forming a peptide bond with the next in the chain, and so on.
All types of RNA are made by transcription of a relevant section (gene) of DNA in the nucleus.
Endoplasmic Reticulum– A series of membranes folded to form channels. The ribosomes are attached to the membranes, it is these membrane channels that proteins are made. These are two forms rough and smooth. Much of the endoplasmic reticulum has a rough appearance because it is studded with tiny black bodies known as ribosomes, this is known as the rough endoplasmic reticulum. The part of membranous sacs do not carry ribosomes and this is known as smooth endoplasmic reticulum.
Golgi apparatus – These collect protein from the endoplasmic reticulum and package and modify it before it is used of excreted from the cell.
Mitochondria – mitochondria are round or sausage-shaped bodies found in large numbers (100plus) in the cytoplasm. The cell has double layers and the inner layer is folded to form internal shelves called cristae. When the food is broken down in aerobic respiration it releases energy for use by the cell. Enzymes that catalyse the breakdown of glucose are dissolved in the internal fluid, while enzymes for the formation of ATP lie on the cristae.
Lysosomes – A function of a lysosome is to digest foreign bacteria that invade a cell and any other unwanted materials such as old organelles. These contain enzymes that aid in the digestion of nutrient molecules and other materials. Whole cell can also be destroyed in this was, a process called autolysis.
Vaculoes may store food or any variety of nutrients a cell might need to survive. They also store waste so that the cell is free from contamination.
Other microstructures including centrioles and cilia, exist in some cells or in most cells at particular times.
Centrioles which are the two tiny hallow cylinders close to the nucleas. They contain microtubles, which can replicate themselves. They do this at the time beginning of cell division, moving to opposite sides of the cell. A spindle of microtubles is formed between them, they help to conrol the separation of the chromosomes to form two new cells.
Cilia these protrude from the cell surface next to mucus secreting cells. They beat to effect transport of the mucus and other materials. The base of a cilium has the same microtubular as the centrioles and is believed to be formed from them.
Functions of the main cells components
Cell Membrane – This is important because it protects the cell with semi-permeable which controls the movement of water, nutrients and waste in and out of the cell. The cell membrane and nucleus are both bound by a phospholipid bilayer. The cell membrane act as a selective barrier to substances entering and leaving the cell. It holds certain receptors sites to which other molecules, such as hormones, can attach. Its function is to also contribute to immunological identity of the cell. It interacts with the surroundings environment, and with adjacent cells. Due to the fluid of the membrane, ‘holes’ or damage can be repaired almost instantaneously.
Nuclear membrane – Acts as a selective barrier to substances entering and leaving the nucleus. Nuclear pores allow communication between the Endoplasmic Reticulum and the nucleus. The nuclear membrane also defines the boundary of genetic material such as DNA.
Nucleus – This controls the cellular activities. It contains chromosomes and thus genetic information. It’s the site of transcription of mRNA from DNA. Ultimately responsible for protein production in the ribosomes. Nuclear division precedes cell division.
Chromosome – This carries theoretical units of inheritance called genes. It contains DNA that is responsible for controlling the protein production. Capable of replication prior to cell division.
Endoplasmic reticulum – Forms an internal cellular transport system.
It enables communication between the cell membrane, the nucleus and the environment. Carries ribosomes that are responsible for the production of proteins (rough). Synthesis lipids from fatty acids and glycerol and transports these to the Golgi body (smooth).
Ribosomes – This binds to the rough endoplasmic reticulum and to the mRNA. It also enables translation of mRNA to produce proteins.
Golgi apparatus – Receives proteins from the ribosomes via endoplasmic reticulum and chemically modifies them for export (particularly in secreting cells). Produces vesicles to transport the modified proteins to the cell membrane for release. It receives and modifies lipids from the smooth endoplasmic reticulum for transport to the cell membrane. It also produces lysosomes containing digestive enzymes.
Mitochondria – complete the oxidation of glucose to release energy. It traps the energy released to form ATP, which is used to power the metabolic functions of the cells.
Cilia – this transports mucus and other materials that may stuck in them to the exterior by continuous rhythmic …show more content…
beating.
There are many materials found in the body moving in and out of cells. The cells are continously needing to take in material from their surroundings and, conversly, exporting or eliminating materials to their surroundings.
States of matter – Matter is the material which has substances and occupies space. Solids, Liquids, and gases are called the three states of matter that must be distinguished. All of these are made from atoms which are the smallest parts and can take part in chemical reactions and molecules which are composed of more than one atom. These atoms are made from smaller particles known as protons and electrons.
Particulate material - Particles such as coal dust, asbestos, carbon etc. is very fine and can cause scarring on tiny air passage ways, enter open wounds where macrophages will need to engulf and digest them.
Ironic material – This material containing atoms that may have a positive or negative charge as a result of gaining or losing electrons. These atoms are called irons or electrolytes. Ionic materials is designated by the relevant charge shown against the atom, e.g. Na+, K+, Cl+.
In solution – substances that are capable of dissolving in a liquid are called solutes. Water is the most common molecule in the human body and most chemicals reactions involve molecules dissolved in water.
Water – water is composed of two hydrogen atoms linked by chemical bonds to one oxygen atom. The hydrogen atoms have a slight positive charges and the oxygen a slight negative charge, so water exists as a polar molecules.
Colloidal forms -
Protein sols – Cytoplasm and blood plasma are both examples of colloid because they are not readily dissolved in water so it classes as protein sol.
Emulsions - An emulsion occurs when one liquid is dispersed in droplets in another, such as fat in milk. This is what happens when bile salts are added to fats in chime; the fat break down into thousands of globules.
Diffusion – Molecules, atoms and irons are in constant motion, more so in liquids and gases, as they are further apart. When there is a large numbers of molecules of a substance and a small number in another area, with no barrier between them, this motion will cause the numbers to even up, which is known as diffusion.
Concentration Gradient - Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. Each are has a different concentration which is known as a concentration gradient. The greater the concentration gradient the faster the rate of diffusion. As the numbers of molecules become more evenly spread the movement of down molecules will eventually slow down and stop. This is termed a state of equilibrium.
Diffusion in the body – In the body, diffusion often takes place through cell membranes. In the lungs there are only two simple squamous epithelial cells separating the gases in the alveoli from the blood in the pulmonary capillaries. No energy is needed for diffusion.
Facilitated Diffusion – Some material diffuse through the cell membrane by a related process known as facilitated diffusion. To facilitate something means to make it easier and the protein channel in the cell membrane assist in transporting molecules into and out of the cells. The concentration gradient is important, as is the number of protein channels available. The channels have a special receptor which changes shape to prevent other molecules from entering until the first molecule has reached the other side. Facilitated diffusion is particularly important in the transport of glucose into the cells, as cells are normally impermeable to glucose.
Osmosis – Osmosis is a special type of diffusion of water molecules. It is the movement of water molecules from an area of high concentration to an area of low concentration through a selectively permeable membrane. The concentration gradient is only concerned with number of water molecules.
Active Transport - Sometimes material passes through cells against a concentration gradient; neither diffusion nor osmosis can account for this. This is active transport. The process is powered by the release of energy from ATP in the cells. The digestion of carbohydrate in the intestine produces glucose and this requires active transport across villi cells against a concentration gradient.
Endocytosis – This is the process of taking materials that are outside the cell into the cell phagocytosis (cell eating) or pinocytosis (cell drinking). Pinocytosis occurs in all cells, but phagocytosis only occurs in special cells such as white blood cells. Endocytosis requires energy from ATP to complete the task.
Exocytosis - This means the process of releasing materials from the cell into the tissue fluid. This method is used for molecules that cannot pass through the cell membrane by diffusion or osmosis.
There are many influences on why materials move in and out of cells. Important factors for diffusion and osmosis include the availability of energy from ATP and the fluidity of cell membranes. The surface area and thickness of selectively permeable membranes will also affect the rates of diffusion and osmosis.
Size - Some molecules are too big to move through a selectively permeable membrane.
The size of the surface must also be large enough to allow sufficient molecules to be transported to accommodate the metabolic processes in cell. For this reason, the surface area to volume ratio for any cell is critical. Size is also important in terms of width and length of a surface carrying out transport of materials. For example; the surface area of single-called alveoli in a person’s lungs, if spread out flat on a surface, would total the area of a football pitch.
Distance – Distance is the same as size, any disease that affects the distance reduces the transportation process. For example; dissolves gases such as oxygen and carbon dioxide pass across the alveolar/capillary interface with ease in a healthy person. A person with pneumonia has extra fluid in the alveoli, resulting in slower gaseous exchange and therefore a lack of oxygen. Diffusion can distribute molecules quickly over a short distance but is very slow over more than a few centimetres.
Temperature – Increasing temperature will also increase kinetic energy, therefore molecules will move faster in diffusion and osmosis. The average speed of molecules depends on temperature and the mass of
molecules.
Concentration gradient – The concentration on each region must be different and this is known as a concentration gradient. The greater the concentration gradient, the faster the rate of diffusion.
Osmotic potential – This is power of a solution to gain or lose water molecules through a membrane. Weaker or more dilute solutions have higher osmotic potentials than concentrated solutions; it follows therefore that pure water has the highest osmotic potential.
Electrochemical gradient – Cells have a difference in electrical charge across the cell membrane, the exterior of the cell membrane carrying positive charges and the interior negative charges. This is called a membrane potential which affects the diffusion of ions across the membrane. The result of this is that positively charged ions will be attracted into the cell and negatively charged ions will be repelled. This operates even where there is no concentration gradient which is referred as electrochemical gradient.
Permeability of cell membrane – some charged or polar molecules and ions diffuse across the phospholipid bilayer very slowly, or not at all. Whereas non-polar molecules diffuse faster. This is because they dissolve in the fatty acid chains or the lipid layer of the cell membrane. Materials such as dissolved oxygen, carbon dioxide, fatty acids, and steroid muscles diffuse in this way quite easily and rapidly.
Channel proteins - Experiments have shown that an artificial bilayer membrane containing no protein results in virtual impermeability to ions such sodium, potassium, chloride and calcium. This suggests that the protein channels are responsible for the permeability of the cell membrane to polar ions and molecules. Shapes of membrane protein channels are varied and related to the ions they allow though. The channels are very small so preventing other molecules from passing.
Carrier molecules – There are many types of carrier molecules in membranes, each specific to a particular substance or group of substances by way of its characteristic binding sites. For example, amino acids and sugars have different binding sites and carrier proteins.
In this assignment I have learnt the various types of cells in a typical animal cell and their functions, also their materials that move in and out of the cells, also what the phospholipid bilayer is and the movement of material into and out of the cell.
Bibliography
Health and social care book level 3
http://en.wikipedia.org/wiki/Lipid_bilayer http://en.wikipedia.org/wiki/Endoplasmic_reticulum http://en.wikipedia.org/wiki/Diffusion
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/cells/cells3.shtml