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Biology > Topic 1 > Flashcards

Topic 1 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

As the size of an organism increases…

A
  • The surface area to volume ratio decreases
  • The diffusion distance increases
  • Metabolic rate (input and output requirements) increase
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2
Q

features of a mass transport system:

A
  1. network to move through (e.g. vessels)
  2. a medium for movement (a fluid e.g. blood)
  3. controlled direction (e.g. blood is moved along pressure gradient created by the heart and the direction of flow is controlled by valves in veins)
  4. maintenance of speed (e.g. contraction of the heart and elastic recoil of artieries helps maintain the pressure gradient, thus speed)
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3
Q

Features of water:

A
  • polar molecule due to uneven distribution of charge wihtin the molecule- the hydrogen atoms are delta + and the oxygen are delta- due to difference in electronegativity
  • water is a polar solvent and can be used to transport many biological molecules (polar molecules can dissolve in water)
  • H bonding between water molecules creates cohesion (to the same molecules) and adhesion (to other molecules) which enables effective transport of water and dissolved substances through xylem vessels.
  • H bonds are relatively strong- water has a high specific heat capacity (a lot of energy required to change temp pf water)- therefore minimising temperature fluctuations in living things (esepcially for aquatic organisms)
  • high surface tension (e.g. pond skaters)
  • can carry thermal energy
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4
Q

arteries have…

A
  • They carry oxydenated blood to the body tissues (other than pulmonary artery)
  • have small lumen to maintain high blood pressure
  • smooth endothelial lining (less resistance/ friction to flow)- tunica intima
  • thick layer of smooth muscle (contract and relax to dilate and constrict blood vessels (controlling diameter)- tunica media
  • elastic fibres (stretch and recoil) -tunica media
  • lots of collagen fibres (for strength and support) - tunica externa
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5
Q

veins have…

A
  • they carry deoxygenated blood to the lungs (except pulmonary vein)
  • large lumen (minimises resistance to flow)
  • thinner layer of smooth muscle and elastic fibres -tunica media
    -reduced collagen fibres -tunica externa
    -valves (to prevent backflow)
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6
Q

capillaries…

A
  • they are very small to fit between cells
  • narrow lumen
  • thin endothelium- one cell thick (to maintain short diffusion distance and fit between cells)
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7
Q

4 chambers and 4 main blood vessels

A
  • right and left atria, right and left ventricle
  • pulmonary vein (lungs to left atrium)
  • aorta (left ventricle to body)
  • vena cava (from body to right ventricle)
  • pulmonary artery (right atrium to lungs)
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8
Q

two types of valves in the heart:

A
  1. atriventrivcular valves (mitral/ bicuspid- left side of heart, tricuspid- right side of the heart)- seperate atria from ventricles
  2. semilunar valves- seperate arteries from ventricles
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9
Q

what is the purpose of the septum of the heart?

A
  • muscle and connective tissue
  • prevents deoxygenated and oxygenated blood mixing
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10
Q

which artery supplies the heart with blood?

A

the coronary artery

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11
Q

describe and explain the difference in cardiac muscle on each side of the heart

A

LHS cardiac muscle is thicker because a higher pressure is required to pump the blood around the body ( a greater distance). The RHS does not require this pressure because blood is travelling a shorter distance: to the lungs and a higher pressure will damage the delicate pulmonary tissue and capillary network.

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12
Q

describe and explain the difference in cardiac muscle on each side of the heart..

A

LHS cardiac muscle is thicker because a higher pressure is required to pump the blood a greater distance (around the body) in the aorta. The RHS does not require this higher pressure because blood is travelling a shorter distance (to the lungs) in the pulmonary artery. A higher pressure would damage the delicate pulmonary tissue and capillary network.

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13
Q

what is atrial systole?

A

-atrias contract (higher pressure in atrias)
-forcing the atrioventricular valves open
-Blood flows into ventricles

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14
Q

what is ventricular systole?

A

-contraction of the ventricles
- atriventricular calves close and semilunar valves open
- blood leaves the left ventricle through the aorta and right ventricle through the pulmonary artery

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15
Q

what is cardiac diastole?

A

-atrias and ventricles relax
-pressure inside the heart chambers decreases
- semilunar valves in aorta and pulmonary arteries close (preventing backflow of blood)

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16
Q

what is the direction of blood flow in the heart?

A
  1. superior vena cava
  2. right atrium
  3. right ventricle
  4. pulmonary artery
    5.pulmonary vein
    6.left atrium
    7.left ventricle
    8.aorta
17
Q

what is atherosclerosis?

A

The hardening of arteries caused by the build up of fibrous plaque called an atheroma. Atheroma formation is the cause of many cardiovascular diseases.

18
Q

The process of Atherosclerosis

A
  1. The endothelial lining (of arteries) is damaged (e.g. by high cholesterol levels, smoking or high blood pressure)
  2. This leads to an inflammatory response, recruiting WBCs to the artery.
  3. over time, the WBCs, cholesterol, calcium salts and fibres build up and harden leading to atheroma formation
  4. The build up of fibrous plaque leads to narrowing og the artery and restricts blood flow thus incrasing blood pressure which in turn damages the endothelial lining and the process is repeated (positive feedback loop)
    - the restriction of blood flow reduces O2 supply, and CO2 removal, decreasing the concentration gradient at exchange surfaces, decreasing the rate of diffusion, decreasing respiration, decreasing ATP produced, leading to cell death (and eventually cardiovascualr diseases)
19
Q

factors increasing risk of atherosclerosis

A
  • genetics (genetic predisposition to high BP)
  • age (arteries become less elastic with age)
  • diet (high cholesterol and saturated fats diet)
  • gender (oestrogen increasing elasticity of arteries)
  • high blood pressure (can damage endothelium)
  • high cholesterol levels
    -smoking (nicotine narrows arteries)
    -physical inactivity (increases obesity risk)
    -obesity (increases BP etc.)
20
Q

Purpose of blood clotting:

A

Thrombosis is known as blood clotting and prevcents blood loss when a blood vessel is damaged, it also prevents the entry of disease causing microorganisms and provides a framework for repair.

21
Q

Blood clotting process:

A
  1. when the blood vessel is damaged, platelets attach to exposed collagen fibres
  2. thromboplastin is released from platelets and triggers the conversion of inactive prothrombin to active thrombin (an enzyme). In order for the conversion to occur, the clotting factors: calcium ions and vitamin K must be present.
  3. thrombin catalyses the conversion of soluble fibrinogen into insoluble fibrin
  4. fibrin forms a network of fibres in which more platelets and RBCs are trapped to form a blood clot.
    - blood clots can obstruct arteries.
22
Q

BMI equation and results

A

weight in kilograns/ (height in metres) squared.
- A BMI under 18 indicates that an individual is underweight
- A BMI above 30 indicates that the individual is obese

23
Q

Waist-to-hip ratio

A
  • can be used to determine how likely a person is to get heart disease based on the distribution of fat in the body
  • A value above 1 suggests a health risk
24
Q

Carbohydrates are made of..
Carbohydrates in the body… (digestion)

A

Only consist of carbon, hydrogen and oxygen. They are long chains of sugar units called saccharides (monosaccharides, disaccharides, polysaccharides).
Monsaccharides are rapidly absorbed in the blood (increasing blood sugar levels)
Disaccharides are digested with hydrolysis reactions (slow release carb)

25
Q

monosaccharides can join together to form disaccharides and polysaccharides by……………. which are formed in …………… reactions (where a water molecule is removed.

A
  1. glycosidic bonds
  2. condensation
26
Q

Glucose is a..
has …. carbon atoms
isomers of glucose..

A
  • is a monosaccharide
  • 6 carbon atoms
  • main substrate for respiration
  • two main isomers: beta and alpha glucose (ABBA - placement of the OH group)
    A lpha
    B elow
    B eta
    A bove
27
Q

Ribose is a …
has … carbon atoms
where is it found?

A
  • monosaccharide
  • 5 atoms (pentose sugar)
    -component of RNA and DNA
28
Q

Disaccharide examples and formation

A

glucose + glucose = maltose
glucose + fructose = sucrose
glucose + galactose = lactose

29
Q

glycogen

A
  • is a polysaccharide
  • main energy storage molecule in animals
  • many molecules of alpha glucose joined together by 1,4 and 1,6 glycosidic bonds (has a large number of side branches)
30
Q

why is glycogen a good storage molecule?

A
  • It has 1,4 and 1,6 glycosidic bonds (has many side branches). The molecule can be hydrolysed easily so energy can be released quickly (as enzymes hydrolyse the terminal branches of the molecule)
  • it is relatively large but compact- maximising the amount of energy it can store. (more energy can be stored in a smaller area)
31
Q

starch:

A

-stores energy in plants and is a mixture of two polysaccharides: amylose and amylopectin

32
Q

starch: Amylose and amylopectin- adaptations for function

A

Amylose- unbranched chain of glucose molecules joined by 1,4 glycosidic bonds. it is coiled and is therefore very compact (can store a lot of energy in a given area)
Amylopectin- branched and made up of glucose molecule joined by 1,4 and 1,6 glycosidic bonds. Due to the presence of many side branches, it is rapidly hydrolysed and digestid by enzymes (energy is released quickly)

33
Q

Lipids:

A
  • are only soluble in organic solvents (e.g. alcohols)
    Saturated lipids (found in animal fats)- don’t contain any carbon- carbon double bonds
    Unsaturated lipids (found in plants)- contain carbon-carbon double bonds
34
Q

Properties of saturated fats vs. unsaturated fats:

A

Unsaturated fats have lower MP and BP because the IM forces are weaker. The double bond creates a kink in the hydrocarbon chain so molecules cannot pack together as closely (there is less surface contact between molecules). Therefore, less energy is required to break the fewer IM forces. Saturated fats are solid at room temp and unsaturated fats are liquid at room temp.

35
Q

Properties of lipids:

A
  • are waterproof (fatty tail is hydrophobic)
  • very compact, and better gram-for-gram energy release than carbs or proteins because more energy is stores in C-O bonds that are hydrolysed.
  • non-polar (insoluble in water)- they are good for storage as they don’t affect the osmotic potential of a cell or interfere with water-based reactions in the cytoplasm.
  • they conduct heat slowly therefore provide thermal insulation
36
Q

Triglycerides vs. phospholipids:

A
  • Triglycerides are made of one molecule of glycerol and three fatty acids joined together by ester bonds (formed in condensation recations). (used as energy reserves in plant and animal cells). Different fatty acids have different R groups, some triglycerides contain a mix of different fatty acids.
  • A phospholipid has two fatty acid tails, a moleucle of glycerol and a phophate group (substituted for the last fatty acid tail). Phosphate heads are hydrophilic and and the tails are hydrophobic. Therefore phospholipids form a bilayer in the cell membrane and heads face watery environments whereas the tails move away from them.
37
Q

What is cholesterol and what is its function?

A
  • a soluble lipid made in the body and is transported by proteins in soluble complexes called lipoproteins- consisting of proteins and lipids
    -cholesterol stabilizes cell membrane with fluctuations in temperature
  • makes up steroid sex hormones (e.g. testosterone and oestrogen)
  • makes bile salts
38
Q

Two types of lipoproteins:

A

High density lipoproteins: ‘good’ cholesterol- formed from unsaturated fats, protein and cholesterol and transports cholesterol from the body tissues to the liver to be metabolised. It reduces cholesterol levels and therefore, decreases the risk of atherosclerosis
Low density lipoproteins: ‘bad’ cholesterol- formed from saturated fats, protein and cholesterol and transports cholesterol from the liver to the blood, thus causing cholesterol levels to increase (increases risk of atherosclerosis)
- The proportion of protein is higher in HDL whereas the proportion of cholesterol and fat in HDL is lower.
- There is a correlation between high levels of saturated fats and high blood cholesterol as saturated fats are one of the components of LDLs

39
Q

Treatments of CVD and side effects:

A
  • Anticoagulants- reduce the risk of clot formation. Risks: uncontrolled bleeding
  • Statins- reduce blood cholesterol levels by blocking the enzyme which produces cholesterol in the liver. Risks: nausea, inflammation, diarrhoea, constipation
  • Platelet inhibitors- make platelets less sticky, reducing the risk of blood clots and atheroma formation. Risks: stomach bleeding- irritates stomach lining
    Antihypertensives:
  • beta blockers- reduce frequency of heart contractions and make them less powerful by blocking response of heart to hormones. Risks: diabetes
  • Diuretics- increase volume of urine, lowing blood volume and pressure. Risks: nausea, muscle cramps, dizziness
  • ACE inhibitors- reduce blood pressure by blocking the conversion of angiotensin I to angiotensin II, which causes arterial constriction. Risks: dizziness, cough, heart arrythmia

Biology (9 decks)

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