Edexcel AS Biology - Topics 1+2 Quiz Answers

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  • Created on: 20-02-13 22:02
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1. Net movement of any molecule from a high concentration to low concentration across a
partially permeable membrane. Continues until equilibrium. Small uncharged polar molecules.
2. Due to the random movement of molecules
3. Down
4. Dynamic equilibrium
5. Millions of alveoli, folded to increase surface area, good blood supply to the lungs
6. Squamous epithelia
7. Condensation reaction
8. Peptide bond
10. R group
11. Hydrogen, hydrogen and disulphide
Phospholipid bilayer
Phosphate head
Lipid tail / 2 fatty acid chains (hydrocarbons)
Carrier protein
Hydrophilic heads attracted to water so are on outside
Hydrophobic tails do not interact with water so are on inside of membrane
Active transport
Facilitated diffusion
18. Adenine ­ Thymine (Uracil) Guanine ­ Cytosine
19. Hydrogen
20. Semi ­ conservative
21. Transcription

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RNA helicase unwinds double helix/unzips DNA/breaks H bonds
RNA polymerase inserts free complementary RNA nucleotides to the exposed DNA
nucleotides/occurs on only 1 of the strands (template)/ T is replaced with U
RNA strand breaks away from template and leaves nucleus via nuclear pore/called mRNA
RNA ligase reforms sugar-phosphate backbone
22.…read more

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Amniocentesis ­ cells from amniotic fluid
Chorionic villus sampling ­ cells from the placental tissue
46. Moral ­ opinion Ethic ­ reasoned explanation
47. Homozygous ­ same Heterozygous ­ different
Nasal/oral cavity
Alveoli ­ gaseous exchange
Isotonic ­ looses the same amount as it gains, no change
Hypertonic ­ loses more water than it gains, decreases in size
Hypotonic ­ gains more water than it loses, increases in size
50.…read more

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Open Insect Large open Simple as few Insufficient for
chamber organs diffusion
No tubes
Single closed Fish Tubes Simple Less efficient for
Heart with 2 High pressure gas exchange
Double closed Birds + mammals Tubes High and low More tubes and
Heart with 4 pressure system effort
1. Aorta
2. Right atrium
3. Right ventricle
4. Semi lunar valve / tricuspid
5. Pulmonary valve
6. Pulmonary artery
7. Pulmonary vein
8. Left atrium
9. Left ventricle
10. Superior vena cava
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57. One complete sequence of filling and pumping blood - Chambers of the heart alternatively
contract (systole) and relax (diastole)
1. Atrial systole ­ atria's contract pumping blood through the semi lunar valves to the
2. Ventricular systole ­ ventricles contract pumping blood up through the arteries.
3. Diastole ­ cardiac muscle is relaxed while the heart fills with blood
1. Thick smooth muscle walls
2. Small lumen
3. Allow high pressure blood
4. Can become arterioles
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Thromboplastin triggers conversion of prothrombin (soluble protein) into thrombin (an
3. Thrombin catalyses the conversion of fibrinogen into fibrin
4. The fibrin fibres tangle and form a mesh which traps platelets and red bloods cells to form
a clot
64. Obesity/high BP/high blood cholesterol/inactivity/smoking/genes/age/gender/salt/stress
Case ­ group of people with a disease are compared with group of people without
the disease
Cohort ­ group of people studied over a period of time to see who develops the
disease and who doesn't.
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Amylose ­ straight chain 1, 4 glycosidic links + Amylopectin ­ branched 1, 6 glycosidic links
Saturated ­ straight chain, single bonds, animal fats and dairy products, solid at RT
Unsaturated - kinked, double bonds, liquid at RT
Stands for: Stands for:
High Density Lipoprotein Low Density Lipoprotein
Protein level? Protein level?
High (mainly proteins) Low (mainly lipid)
Saturated/unsaturated? Saturated/unsaturated?
Unsaturated Saturated
Transports... Transports...…read more

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APOA ­ major protein in HDL, mutations are associated with low HDL levels +
reduced removal of cholesterol from blood, increasing risk of CHD
APOB ­ major protein in LDL, mutations associated with higher levels of LDL +
increased risk of CHD
APOE ­ found in HDL + LDL, involved in removal of excess cholesterol from blood to
77.…read more


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