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54 Cards in this Set
- Front
- Back
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What is a nucleoside? |
A molecule formed when an organic base combines with the first carbon on deoxyribose. |
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Name the 4 nucleosides |
Deoxyadenosine Deoxycytidine Deoxyguanosine Deoxythymidine |
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How far apart is each nucleotide from each other? |
0.34nm |
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What is the diameter of the alpha helix? |
2nm |
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What is the structral difference between purines and pyramidines? |
The amount of carbon rings... There are 2 in the purines and only 1 in the pyramidines |
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What does DNA helicase do? |
'unzips' the two strands of DNA |
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What does polymerase III do? |
Adds copmlementary nucleotides to the 3' end of the new DNA strand, starting at the primer. |
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What does polymerase I do? |
Fills in the gaps between primers and nucleotides on the lagging strand in discontinuous replication. |
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What is a telomere? |
A repeat sequence at the end of chromosomes that binds to stabalising proteins |
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How is DNA packaged? (3mks) |
1. Core DNA wraps around histones H2a, H2b, H3 and H4 to form a nucleosome. 2. Linker DNA connects nucleosomes, while H1 histones keep them in place. 3. The strand then coils to form a chromatin, then a chromosome. |
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What are the 4 stages of translation? |
Initiation Elongation 1 Elongation 2 Elongation 3 Elongation 4 Termination |
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What type of bonds join AAs in the primary structure of a protein? |
Peptide |
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Nae the 2 ways a polypeptide chain can fold in the secondary structure of a protein |
Alpha helix Beta pleated sheet |
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What are the bonds holding the secondary structure of a protein together? |
H+ Bonds |
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Which parts of the AA interact to form the tertiary structure of a protein? |
R groups |
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Which types of bonding hold together the tertiary structure of a protein? |
Disulphide bridges Hydrophobic interactions Hydrogen bonds Electrostatic bonds |
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How do Protein Kinases regulate protein activity? (3mks) |
They phophorylate the amino acids in the primary structure of the protein. They bind ATP to the protein and transfer the gamma-phosphate to a specific amino acid. This changes the conformation of the protein because the addition of a negative phosphate group will repel sections of the protein that were previously attracted to each other. |
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What are the 5 classes of antibody? |
IgG IgE IgD IgM IgA |
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What is the most common immunoglobulin? |
IgG |
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What are IgG responsible for? |
Resistance against viruses, bacteria and bacterial toxins |
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Where do IgE attatch? |
They attatch as individual molecules to the exposed surfaces of basophils and mast cells |
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What do IgD do? |
They sit on the surface of a B cell and bind antigens to their extracellular fluid. |
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What is IgM? |
This is the first class of antibody secreted after an antigen is encountered. The conc of IgM decreases as IgG is produced. |
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Which type of immunoglobulin is responsible for blood type incompatibilities? (anti-A and anti-B antibodies) |
IgM |
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Where are IgA found? |
In glandular secretions such as tears, musuc, saliva and semen, |
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How long is an Oligosaccharide? |
3-20 monosaccharides long |
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How is glucuronic acid produced? |
By oxidising the 6th hydroxyl group of glucose |
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How are alcohols produced from sugars? |
Reducing the aldehyde at the first carbon |
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How is a sugar phosphate produced? |
Adding a phosphate group to a monosaccharide |
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How are amino sugars produced? |
Replacing the hydroxyl group on the second carbon of the sugar. |
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glucose + glucose = |
Maltose |
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glucose + galactose = |
Lactose |
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glucose + fructose = |
sucrose |
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What is the storage carbohydrate molecule in animals? |
Glycogen. It is highly branched every 8-10 units for rapid glucose release |
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What are the 2 forms of starch? |
20-25% Amylose and 75-80% Amylopectin |
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How is amylose arranged |
.A linear chain of alpha glucose that coild helically when in water |
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How is amylopectin arranged? |
A linear chain of alpha glucose molecules with branching ever 20-25 units. |
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What is cellulose? |
A linear chain of beta glucose found in plant cell walls. |
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What are the two forms of cellulose and how are they arranged? |
crystalline cellulose are regular chains of cellulose arragned in microfibrils held with H bonds. amorphous cellulose are less ordered and contain up to 10% other monosaccharides than beta glucose |
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What is chitin? |
an unbranched chain on N-acetylglucosamine joined with 1-4 glycosidic bonds. |
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Where is chitin found? |
Fungal cell walls, crustacean shells and arthropod exoskeletons |
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What is the main structural component of the cell wall of a gram positive bacter? |
Peptidoglycan. |
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Which are the 2 alternating chains found in peptidoglycan? What are they held together by? |
N-acetylglucosamine and N-acetylmuramic acid 1-4 glycosidic bonds hold the molecules together in the chains, and pentaglycine bridges hold the chains together. |
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Name the 5 main biological functions of lipids |
1. Energy Storage 2. Membrane structure 3. Thermal insulation 4. Light absorbtion 4. Hormones 5. Vitamins |
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General formula of fatty acids |
CH3(CH2)nCOOH |
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Wht chain length fatty acids are the most common? |
16 and 18 |
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Which have lower melting points? Saturated or unsaturated fatty acids? |
unsturated. |
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Phopholipids contain which? |
2 fatty acids bound to a glycerol as well as a phosphate containing compount. |
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Caretenoids are used in what? |
Photosynthesis - absorbs light and transfers energy to chloryphll Rhodopsin in the eye Found in natural compounds like rubber. |
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Steroid structure? |
3 six carbon rings and 1 5 carbon ring. |
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What are Eicosanoids |
A group of lipids derived from fatty acids that are found in cell membranes, where they act as signalling molecules. They mediate things like inflammation. |
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Wax structure |
esters of long chain fatty acids and long chain alcohols |
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What are glycolipids? |
Sugar containig compounds that are made when a glycosidic bond is formed between a carbohydrate and a large lipid. |
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Which vitamins are lipid soluble? |
A, D, E and K |
