Biology Notes

1. Phospholipid: Molecule that forms a double-layered cell membrane; consists of a glycerol, a phosphate group; and two fatty acids.
2. Selectively permeable (Semi): Condition or quality of allowing some, but not all, materials cross a barrier or membrane.
3. Receptor: Protein that detects a signal molecule and performs an action in response.
4. Diffusion: Movement of dissolved molecules in a fluid or gas from a region of higher concentration to a region of lower concentration.
5. Osmosis: Diffusion of water molecules across a semipermeable membrane from an area of higher water concentration to an area of lower water concentration.
6. Passive Transport: Movement of molecules across the cell membrane without energy input from the cell.
7. Active Transport: Energy requiring movement of molecules across a membrane from a region of lower concentrations to a region of higher concentration.
8. Facilitated Transport (Diffusion): Diffusion of molecules assisted by protein channels that pierce a cell membrane.
9. Exocytosis: Release of substances pit a cell by the fusion of a vesicle with the membrane.
10. Endocytosis: Uptake of liquids or large molecules into a cell by inward folding of the cell membrane.
11. Isotonic: Solution that has an equal concentration of dissolved particles compared with another solution.
12. Krebs Cycle: Process during cellular respiration that breaks down a carbon molecule to produce molecules that are used in the election transport chain.
13. Calvin Cycle: Process by which a photosynthetic organism uses energy to synthesize simple sugars from CO2.
14. Mitochondria: Bean-shaped organelle that supplies energy to the cell and has its own ribosome and DNA.
15. tRNA: Brings amino acids from the cytoplasm to a ribosome to help make the growing protein.
16. mRNA: Is an intermediate message that is translated to form a protein.
17. RNA: Nucleic acid molecule that allows for the transmission of genetic information and protein synthesis.
DNA… A-T, G-C
RNA… A-U, T-A, G-C, C-G
1. Rough ER - where ribosomes are located. Ribosomes manufacture (synthesize) proteins
B. Smooth ER - no ribosomes, where lipid synthesis takes place
2. ENDOPLASMIC RETICULUM (E.R.) - complex system or network of interconnected membranes, canals, or channels. Connected to cell membrane, nuclear membrane, and organelles
Function = TRANSPORT SYSTEM
3. GOLGI APPARATUS (BODIES) - series of flattened, membranous sacs near the nucleus
Function = "Refining", "Packaging", Delivery of proteins.
4. MITOCHONDRIA (-ion = sing.) - Usually numerous, double layer membrane - inner layer folded to form CRISTAE.
5. LYSOSOMES - quite variable in size and shape. Contain powerful digesting enzymes - breakdown and destroy foreign particles, microorganisms, damaged or worn out cells and cell parts
6. VESICLES - tiny sacs in which substances are transported
1. Diffusion: Spreading of molecule from high concentration to low concentration. This is following entropy. No energy needed.
2. Osmosis; H20 diffusing through membrane.
RNA is a type of nucleic acid called ribonucleic acid:
• The RNA nucleotides are joined to form a single strand.
• The nucleotides are joined by a bond between the sugar of one nucleotide and the phosphate of the next.
RNA differs from DNA in the following ways:
• RNA is single stranded while DNA is double stranded.
• RNA has a sugar called ribose while DNA has a sugar called deoxyribose.
• RNA has the base uracil while DNA has the base thymine.
There are two types of RNA that need to be known for this topic. The first is mRNA. This is formed in the nucleus of the cell. It rewrites the sequence of bases of a section of DNA in a process called transcription.