Bio Cell Summary

Yr 12 Biology Summary Notes Rangitoto College 2006
STRUCTURE AND FUNCTION IN CELLS

Achievement Standard 90464 – Biology 2.8 – Describe cell structure and function
TYPES OF CELLS • PROKARYOTIC CELLS = more primitive, unicellular, have no organised nucleus, no membrane-bound organelles, genetic material is 1 circular DNA molecule, can have tiny extra rings of DNA called plasmids, all have cell walls e.g. bacteria and blue-green algae • EUCARYOTIC CELLS = unicellular or multi-cellular, plant and animal cells, have a nucleus, have membrane-bound organelles, DNA is wound around histone proteins e.g. all plant and animal cells, Euglena, Paramecium, Amoeba, yeast

|ORGANELLE |WHERE FOUND |STRUCTURE |FUNCTION |
|Cell(Plasma) |Plant & animal cells, |- 2 layers of phospho-lipids |- boundary between cell and environment |
|Membrane |All pro & eukaryotes |- hydrophilic end = to water |- regulates flow of substances in and out |
| | |- hydrophobic end = to centre |- proteins involved in transport |
| |surrounds cytoplasm |- globular proteins in layer |- cell recognition |
| | |- carbohydrates project out | |
| | |- cholesterol in lipid tails | |
|Cytoplasm |Plant & animal cells |- jelly-like fluid made up of water, ions, |- where most cell reactions occur |
| |All pro & eukaryotes |small molecules and proteins |- supports organelles |
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| |inside cell membrane and | | |
| |outside nucleus | | |
|Chromosomes/ |Plant & animal cells, |- made up of DNA (deoxy-ribose nucleic acid)|- carries genetic code for making proteins e.g.|
|Genetic Material |All pro & eukaryotes | |enzymes, hormones |
| | |- with histones if eukaryotic | |
| |inside nucleus if eukaryotes | | |
|Ribosome |Plant & animal cells, |- made of ribosomal RNA that is made in the |- site of protein synthesis |
| |All pro & eukaryotes |nucleolus of the nucleus |- free ribosomes make proteins needed in |
| | |- made of 2 sub-units |cytoplasm |
| |free in cytoplasm or on rough |- non-membranous |- ribosomes on ER (rough ER) make proteins to |
| |ER, commonly found in secretory| |be transported/ secreted out of cell |
| |cells | | |
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|Nuclear |Plant & animal cells, |- double membrane (outer and inner) |- surrounds nucleoplasm and DNA |
|Membrane |Eukaryotes only |- connected to ER |- large pores/holes to allow material in and |
| | | |out |
| |surrounds nucleus | | |
|Nucleus |Plant & animal cells, |- large round organelle that contains |- contains DNA that codes for all proteins |
| |Eukaryotes only |genetic material |needed by the cell |
| | |- has a nucleolus (dense attaining region) |- nucleolus makes RNA to make ribosomes and |
| |centre of animal cell, side of | |protein synthesis |
| |plant cell | | |
|Mitochondrion/a |Plant & animal cells, |- oval shape |- aerobic respiration process = the breakdown |
| |Eukaryotes only |- inner and outer membrane |of glucose in the presence of oxygen to provide|
| | |- inner forms folds (large SA) called |the cell with energy in the form of ATP |
| |free in cytoplasm, |cristae (have enzymes) |(happens cristae & matrix) |
| |found in large numbers in cells|- fluid is called the matrix |- outer membrane controls entry & exit of |
| |that need a lot of energy | |materials |
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|Vacuole |Plant & animal cells |- fluid-filled spaces surrounded by a |- turgidity, storage of food and H2O, storage |
| |Eukaryotes only |membrane |of toxic substances for later release and |
| | |- many and smaller in animals |contain pigments (provide colour) in PLANTS, |
| |centre of plant cell, |- one large & central in plants |- storage of food in animals and to get rid of |
| |scattered in animal | |water (contractile) |
|Endoplasmic |Plant & animal cells, |- flattened membrane stacks throughout the |- extensive transport system |
|Reticulum (ER) |Eukaryotes only |cell |- collection, storage and distribution of |
| | |- has a system of channels |proteins, lipids and steroids |
| |throughout cell and connected |- rough ER with ribosomes |- rough ER produce and package proteins made by|
| |to nuclear and cell membrane. |- smooth ER without |ribosomes |
| |Secretory cells have lots of | |- smooth ER synthesises lipids and steroids |
| |rough ER e.g. liver, pancreas. | |which bud off in vesicles and go to the Golgi |
| |Glands and testes have lots | |apparatus for secretion, makes membrane |
| |smooth ER to make lipid based | | |
| |hormones (steroids) | | |
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|Lysosome |Plant & animal cells, |- small vesicles surrounded by membrane |- release enzymes to break down worn-out |
| |Eukaryotes only |formed from Golgi Body containing digestive |organelles |
| | |enzymes |- digest material taken into cell or release |
| |free in cytoplasm | |enzymes out of cell |
|Golgi Body/ |Plant & animal cells, |- made of stacks of flattened sacs called |- transport and storing of lipids from ER |
|Apparatus |Eukaryotes only |cisternae |- modifying and secreting chemicals from ER |
| | |- form from vesicles that pinch off end of |like enzymes, lipids |
| |in cytoplasm, |rough ER |- formation of lysosomes |
| |common in secretory cells in |- 1 side of Golgi Body receives vesicles | |
| |animals, only have 1 Golgi, |from ER and the other side releases new | |
| |plants have many |chemicals for transport through cytoplasm | |
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|Cell Wall |Plant cells only, |- made of tiny cellulose fibres in a |- strength to support cell |
| |All prokaryotes |criss-cross pattern |- can become turgid without bursting |
| | |- permeable to water unless lignin added so | |
| |outside cell membrane |needs channels called plasmodesmata | |
|Chloroplast |Photosynthetic plant cells |- oval shape |- site of photosynthesis = using chlorophyll to|
| |only, |- inner and outer membrane |absorb light and combine CO2 and H2O to produce|
| |Eukaryotes only |- flattened sacs called thylakoids are found|glucose (chemical energy) and O2 |
| | |in stacks called grana |- chlorophyll is a green pigment that traps |
| |free in cytoplasm |- fluid is stroma |light |
| | |- can store starch grains | |
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|Centrioles |Animal cells only, |- made of 2 rod shaped structures composed |- for cell division |
| |Most unicellular protists |of bundles of microtubules |- move to opposite ends of cell and form |
| | |- at right angles to each other |spindle/”muscle fibres” to pull chromosomes |
| |in cytoplasm just outside the | |apart |
| |nucleus | | |
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|Cilia |Animal cells only, some |- many, short “hair-like” projections |- move chemicals about and over surface of cell|
| |unicellular protists |- made of 9 pairs of fine tubules around 2 |e.g. line trachea of human |
| | |central filaments |- move the cell e.g. Paramecium |
| |project from surface | | |
|Flagellum/a |Animal cells only, some |- long ‘hair-like” projection |- help a cell to move e.g. sperm cell, bacteria|
| |unicellular protists, |- made of 9 pairs of fine tubules around 2 | |
| |prokaryotes |central filaments | |
| | |- usually occur singly | |
| |project from surface | | |
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|Eyespot |Photosynthetic |- small orange granule containing |- detects light intensity so cell can move |
| |unicellular organisms or |carotenoids pigment that is light sensitive |towards light and maximise photosynthesis |
| |protists only | | |
| |e.g. Euglena | | |
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| |found at front end | | |
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|Contractile |Freshwater unicellular animals |- membrane-bound organelles that are |- maintain water balance in cell by collecting |
|Vacuole |only, e.g. Paramecium, Amoeba |surrounded by mitochondria |water that comes in by osmosis and expelling |
| |(Protozoans) | |it, using energy, out of the cell |
| | | |- stops cell exploding |
| |found in cytoplasm | | |
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|Oral Groove |Some unicellular animal |- ciliated channel (has cilia) |- beating cilia pull surrounding fluid into |
| |protists only, | |oral groove for feeding |
| |e.g. Paramecium | |- food vacuole forms at the end of the oral |
| | | |groove, then digested |
| |found on one side | | |

CELLS THAT DON’T HAVE NUCLEI = Phloem sieve tube cells (transport sugars) Red blood cells (carry oxygen)
The lack of a nucleus allows more room for their respective functions.