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A Level Biology > Topic 1 > Flashcards

Topic 1 Flashcards

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1
Q

Why dont unicellular / very small organisms have a heart

A

No mass transport, diffusion is sufficient due to a high SA to Volume Ratio with very small diffusion distances

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2
Q

Why do Multicellular / larger organisms have a heart

A

Mass Transport transports nutrients/waste - “Overcome LIMITATIONS of diffusion”- Diffusion insufficient - small SA to Vol ratio - Large diffusion distance

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3
Q

Properties of Water

A

Good solvent
Good Transport Medium
Good Coolant
Cohesive Nature for surface tension

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4
Q

Why is water a good solvent and why important

A

Dipolar molecule - Surrounds solute - Hydrogen bonding. All metabolic reactions occur in solvents

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5
Q

Why water is a good Transport medium:

A

Dipolar molecule - H-bonds - Cohesion for “flow” (I.e. in transpiration)

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6
Q

Describe Arteries

A
  • Smooth endothelium - reduce friction
  • Narrow lumen - Maintains high BP
  • More collagen fibres - Recoil - Withstands high BP/Provides strength
  • More smooth muscle - Contracts/Relaxes - Maintains/withstands high BP
  • More elastic fibres - Stretch/recoil - Maintains/Withstands high BP
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7
Q

Veins:

A
  • Less collagen/smooth muscle/elastic fibre - low BP
  • Wide lumen - Maintains low BP
  • Valves - Prevent backflow of blood
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8
Q

Capillaries:

A
  • Walls one cell thick - short diffusion distance
  • Lumen one cell thick - slows blood flow - gives time for chemical exchange
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9
Q

Stages of Cardiac Cycle

A

Atrial Systole:
Ventricular systole:
Diastole

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10
Q

Diastole

A

Atria and Ventricles relax - Elastic recoil = lower pressure - SL valves shut - Atria and C.arteries fill with blood.

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11
Q

Ventricular systole:

A

Ventricles contract - SL valves open - AV valves shut - Blood flows through aorta and P. artery

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12
Q

Atrial Systole:

A

Atria contract - Blood pushed into ventricles - Through AV valves - SL valves shut

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13
Q

Name the Cardiac Vessels and Blood flow through them

A

Aorta: To body - From Left Ventricle
Pulmonary artery: To lungs - From Right Ventricle
Pulmonary vein: To Left Atrium - From Lungs
Superior Vena Cava: To Right Atrium - From Head and Arms
Inferior Vena Cava: To Right atrium - From Lower body

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14
Q

Atherosclerosis Definition

A

Thickening or hardering of arteries caused by a buildup of plaque
* Disease process - Leads to CVD

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15
Q

Process of atherosclerosis

A
  1. Endothelial damage (High BP)
  2. Inflammatory response - WBCs in artery wall - Accumulate cholesterol
  3. Fatty deposit - Atheroma
  4. Calcium salts + Fibrous tissue - Plaque formation (Calcification)
  5. Positive feedback - Narrowing = Higher BP
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16
Q

Blood Clotting Cascade:

A
  1. Endothelial damage + platelets release thromboplastin
  2. Thromboplastin activates an enzyme
  3. Enzyme catalyses prothrombin&raquo_space; Thrombin (enzyme) - Ca2+ present
  4. Thrombin catalyses Fibrinogen&raquo_space; Fibrin (Insoluble)
  5. Fibrin mesh forms clot
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17
Q

Causes of Angina/Myocardial Infarction

A

Coronary arteries narrowed - not enough oxygen and glucose reaching cardiac muscle - no aerobic respiration - lactate buildup - Angina/Heart attack

Coronary arteries blocked - no blood to cardiac muscle - Ischaemic - muscle cells die - Myocardial Infarction

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18
Q

Cause of Stroke

A

Arteries leading to brain blocked - Not enough oxygen to brain cells

19
Q

Risk Factors for CVD

A

Genetics: Alleles might be responsible for CVD risk
Diet: High Saturated fat - More LDL/ High Salt - Higher Blood pressure
Age: Greater risk with age - Endothelial damage increases w/time
Gender: Men are at greater risk - Oestrogen may provide protection
Smoking: Hardens arteries - less elasticity in arteries - adrenaline produced - high BP
Inactivity: Inactivity raises blood pressure - endothelial damage

20
Q

Correlation Does not

A

Mean causation

21
Q

Features of a good study

A
  • Clear Aim - Design appropriate to hypothesis
  • Representative sample - min. selection bias - min. Participant drop-out
  • Produces “Valid” data - measures what its supposed to measure
  • Produces “Reliable” data - data is repeatable/reproducible
  • Large sample - results couldn’t have occurred by chance
  • Variables controlled
22
Q

Cohort studies

A

Large group of people - separated into group with condition & group without over time - exposure to risk factors compared - correlations drawn - conclusion made

23
Q

Case-control studies

A

Group exposed to risk factor and group not exposed followed over time - each group divided into those who develop condition and who don’t - compare outcomes and draw conclusions

24
Q

Risk

A

Probability of - unwanted event/outcome”

25
Q

Perception of risk

A

People overestimate risk if:

Risk is involuntary, unnatural, unfamiliar, dreaded, unfair, small

People underestimate risk if:

Risk is voluntary, natural, there is lack of information, or peer pressure is involved (e.g alcohol/smoking)

26
Q

What food group contains the most energy per gram

A

Lipids have most energy per gram - followed by alcohol, protein and carbohydrates.

27
Q

Monosaccharides

A

Single sugar units - (CH20)n - Between 3-7 Carbon atoms - e.g. Glucose, galactose, fructose

28
Q

Disaccharides

A

‘Double sugar” - glycosidic bond - condensation reaction of 2 monosaccharides - e.g. Sucrose, maltose

29
Q

Polysaccharides

A

Polymer made of simple sugar monomers - glycosidic bonds - long chains - condensation reaction - sparingly soluble

30
Q

Starch Characteristics

A

Storage pollysaccaride of plants
Constructed from amylose and amylopectin
1,4 and 1,6 bonds between alpha glucose molecules
Branched or helix means easier for hydrolysis back to glucose
Insoluble so it has no osmotic effect

31
Q

Glycogen Characteristsics

A

Polysaccharide of glucose - animal energy storage

1-6, glycosidic bonds - Branched chain for rapid hydrolysis

In humans it is stored in the liver and muscles

32
Q

What is a lipid / solubility

A

General term for fats/oils
Insoluble in water - soluble in organic solvents, e.g. ethanol

33
Q

What is a triglyceride

A

Made up of one glycerol and 3 fatty acid chains joined by condensation reactions - 3 water molecules released - 3 ester bonds form

34
Q

Saturated VS Unsaturated Fats

A

Saturated: No Carbon-Carbon double/triple bonds in fatty acid chain
Unsaturated: Contains one (Monounsaturated) or more (polyunsaturated) Carbon-Carbon double or triple bonds

Saturated fats have a higher melting point and have straight chains
Unsaturated fats have a lower melting point and have kinked chains

35
Q

Why is smoking a risk factor

A
  • CO binds to hemoglobin - less oxygen - faster heart rate
  • Nicotine - adrenaline production - arteries constrict - faster heart rate - higher BP
  • Damages artery lining - atherosclerosis
  • Linked with reduction in HDL level
  • Quitting smoking will reduce CVD risk!
36
Q

Antihyperintensives

A

Include calcium channel blockers, ACE inhibitors and diuretics

Benefits: Reduce blood pressure - reduce endothelial damage - reduce risk of atherosclerosis

Risks: Could cause low blood pressure and kidney failure

Side effects: Dizziness, nausea, Kidney failure

37
Q

Anticoagulants

A

Benefits: Prevents formation of blood clots in the arteries

Risks: Risk of bleeding could outweigh benefits

Side effects: rashes, nausea, diarrhea, bruising

38
Q

Statins

A

Benefits: lower LDL in the blood - inhibiting an enzyme that helps produce LDLs in the liver

Risks: May increase risk of death by non-vascular causes - May increase GI and respiratory cancer risk

Side effects: Tiredness, disturbed sleep, nausea, vomiting, diarrhea, muscle weakness, headache

39
Q

Platelet inhibitors

A

Benefits: prevents platelet aggregation - prevents clot formation

Risks: risk of bleeding

Side effects: rashes, nausea, diarrhea, bruising

40
Q

Core Practical 1 - Daphnia

A

Immobilise daphnia using cotton wool fibers
Place solution onto cotton
Count heart beats under microscope per unit time
Repeat 3x at each concentration to identify and exclude anomalies

41
Q

Core Practical 2 - Vitamin C

A

“TITRATION” - using micropipette/burette
Mention DCPIP color change (Blue to Colorless)
First titrate known concentration of ascorbic acid solution
Measure volume of juice needed to decolorize DCPIP (not vice-versa)
Repeat 3x for each juice to identify and exclude anomalies
Calculate concentration of Vitamin C per 100g of each fruit juice

42
Q

HDL cholestrol

A

Takes cholesterol from blood to liver to be broken down. Caused by saturated fats

43
Q

LDL Cholestrol

A

Consumption of unsaturated fats, takes cholestrol from liver to blood

A Level Biology (4 decks)

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