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Biology 1 > Organisation > Flashcards

Organisation Flashcards

1
Q

Explain the financial impact on the UK economy of the increasing number of people becoming obese.

A

Increased costs for NHS because they have to pay for medication.

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2
Q

Explain how amylase breaks down starch in terms of the lock and key theory.

A

Starch (substrate) binds to the active site of the enzyme as the shape of the active site and substrate are complementary so form an enzyme-substrate-complex. A chemical reaction then occurs to release/produce smaller molecules (sugars) and amylase is not used up

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3
Q

Describe the effect of temperature on enzyme activity.

A
  • Initially as temperature increases enzyme activity increases because the enzyme gains kinetic energy and therefore there are more frequent and successful enzyme-substrate collisions
  • Optimum temperature is where enzyme activity is the best
  • Once temperature gets too high, the enzyme denatures (active site changes shape) so the substrate shape can no longer fit on to enzymes active sites shape meaning the reaction can no longer be catalysed
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4
Q

RPA 3: Explain why at very low and very high temperatures iodine doesn’t become yellow/brown.

A

Doesn’t become yellow/brown because starch is still present as it hasn’t been broken down so remains blue. At very low temperatures enzymes don’t have enough kinetic energy so fewer enzyme-substrate-complex collisions. At very high temperatures enzymes denature (active site changes shape) so the substrate shape can no longer fit on to the active site meaning reaction can’t be catalysed

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5
Q

Which cell structure in a mesophyll cell is not found in a root hair cell?

A

Chloroplasts (underground so no light to absorb)

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6
Q

What cells control the rate of water loss?

A

Guard cells (control the stomata)

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7
Q

What is the term for water being taken up the roots, up the plant and lost from the leaves?

A

Transpiration stream.

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8
Q

Explain why the rate of water loss is lower at night.

A

Lower light intensity so stomata is almost completely closed by guard cells (guard cells are light sensitive).

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9
Q

How can you tell a tumour is malignant?

A

It has spread to other organs through the bloodstream forming secondary tumours and so are cancerous

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10
Q

Explain how a lower number of blood components can cause symptoms of tiredness.

A

Less RBCs so less haemoglobin to bind to oxygen, so less oxygen transported around the body to cells. Less (aerobic) respiration so less energy released.

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11
Q

Explain how a lower number of blood components can cause symptoms of frequent infections.

A

Less WBCs so fewer antibodies and antitoxins produced and less phagocytosis (weaker immune system) so less pathogens killed.

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12
Q

Explain how a lower number of blood components can cause symptoms of excessive bleeding.

A

Less platelets so blood does not clot as easily - cell fragments are sticky.

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13
Q

Explain why a tumour blocking the gall bladder from the small intestine affects fat digestion.

A

Less bile reaching the small intestine as the gall bladder stores bile. Less emulsification of fats so a smaller surface area for lipase enzymes to break down. No bile also means pH of small intestine is not neutralised (bile is alkaline) so lipase is not at its optimum pH to break down fats. Lipids broken down less efficiently

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14
Q

Name 3 chemical substances carried by the plasma.

A
  • amino acids
  • glucose
  • hormones
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15
Q

Describe how white blood cells aid infections.

A

A part of the immune system. Can produce antitoxins which neutralise/counteract toxins released by bacteria. Can also produce antibodies which are proteins specific to a pathogen as complementary to its antigen protein so will kill the pathogens. Can also engulf and kill pathogens by phagocytosis.

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16
Q

Explain the lock and key theory of enzyme action.

A

Enzymes active site shape is complementary so the substrates shape fits onto it. They bind and the substrate is broken down (as an enzyme-substrate-complex is formed) where a chemical reaction occurs. Products will be released whilst the enzyme remains unchanged.

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17
Q

Explain why enzymes catalyse specific reactions.

A

Active sites have a specific shape complementary to one specific substrates shape.

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18
Q

RPA 4: describe how a student can carry out a test for glucose.

A

Add Benedict’s solution to a test tube with sample and gently heat in a water bath. If glucose is present solution will turn from blue to brick red/orange/green.

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19
Q

Explain why a plant in light contains both glucose and starch.

A

Glucose produced from photosynthesis. Excess glucose converted to starch for storage as starch is insoluble.

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20
Q

Give 3 further tests to investigate glucose and starch production in plants.

A
  • Different types of plants
  • Light intensity
  • Concentrations of glucose and starch
21
Q

Describe the effects of liver failure on the human body.

A
  • Little/no bile produced. Lipids not emulsified so surface area will not increase so lipase enzymes will work less efficiently. pH will not be neutralised in small intestine so other enzymes activity will not work at optimum pH as a result may lose weight as have a smaller appetite (slower metabolism).
  • Lactic acid not oxidised. Toxic lactic acid build up so prolonged muscle fatigue.
22
Q

Explain what an enzyme is.

A

A biological catalyst made of chains of amino acids (proteins) that speed up the break down of food into small soluble molecules that can be absorbed into the bloodstream. Specific to specific reactions without being used up.

23
Q

Explain the effect of improper break down of starch.

A

Less glucose absorbed so less glucose available for respiration meaning less energy released so less metabolism, more fat has to be used up for energy

24
Q

Explain the effect of improper break down of proteins.

A

Less amino acids absorbed so fewer for making new proteins for repair/replacement.

25
Q

Explain the effect of improper break down of lipids.

A

Less fatty acids absorbed so fewer available to store as fat in the body for warmth.

26
Q

Explain what is a safety measure to take when using biuret reagent.

A

Clean up spills immediately as it is corrosive.

27
Q

How is the volume lost from leaves controlled?

A

Opening and closing the stomata (with guard cells).

28
Q

Explain 2 disadvantages of a lack of glucose in plants and animals [one in plants one in animals]

A
  • Less amino acids made so less proteins produced which are needed for growth (plants)
  • Less respiration so less energy released meaning less metabolism, fats will need to be used up for energy (animals)
29
Q

Explain how ions moving into guard cells open the stomata.

A

Ions increase the concentration of guard cells so they become less dilute. Water will therefore move into the guard cells by osmosis causing them to swell unevenly as inner walls are less flexible than the outer walls.

30
Q

Say the term for how water moves from the roots to the leaves

A

A transpiration stream through the xylem.

31
Q

Describe how water moves from the roots to the atmosphere and what this creates

A

Moves into roots by osmosis. Pulled up by the xylem and evaporates out of the leaves through the stomata (continuous stream creates a transpiration stream)

32
Q

Describe how glucose is transferred from the small intestine to muscle cells.

A

Absorbed into bloodstream by diffusion. Carried by plasma and then diffuses into muscle cells via capillaries.

33
Q

What conditions can increase rate of water loss? (give 2)

A
  • Warmer
  • More windy
34
Q

What is one advantage and disadvantage of mechanical valves?

A

advantage:
- less likely to be rejected
disadvantage:
- risk of blood clot so have to take blood thinning drugs

35
Q

What is one advantage and disadvantage of biological valves?

A

advantage:
- don’t have to take blood thinning drugs
disadvantage:
- more likely to be rejected (may have to take anti-rejection drugs which suppress immune system)

36
Q

Describe the test for glucose and give the result.

A

Add Benedict’s solution and then heat in a water bath. Blue -> brick red (depending on concentration of reducing sugar)

37
Q

How can you measure the rate of transpiration?

A
  • Set up a potometer with a plant cut at an angle, air tight around boiling tube
  • Measure uptake of water by starting stopwatch and recording distance moved by bubbles per unit time across the capillary tube
  • Calculate supposed rate: distance/time
38
Q

Is the rate of transpiration recorded by a potometer accurate?

A

No as not all of the water that is taken by the plant is due to transpiration (water lost) as water taken up might be used for photosynthesis or by the cells to maintain turgidity

39
Q

Describe the effects of liver failure on the human body

A
  • Less bile produced by liver so less lipids can be emulsified so they will have a smaller surface area and pH of SI will not be neutralised so enzymes will not work as efficiently
  • Lactic acid will not be broken down (oxidised in the liver) so a build up of lactic acid in the body which is toxic and prolongs muscle fatigue
40
Q

Explain how the human circulatory system is adapted to:
* supply oxygen to the tissues
* remove waste products from tissues

A
  • Double circulatory system means more blood can be pumped to the whole body more efficiently
  • Pulmonary arteries and veins, aorta, vena cava
  • Capillaries
  • Red blood cells
  • Veins that have valves
  • Plasma carries waste to be excreted ie urea
41
Q

Explain the disadvantage of having less ventricles / valves.

A

Increased risk of backflow of blood so deoxygenated and oxygenated blood mixes so less oxygenated blood reaches body cells for aerobic respiration, so less aerobic respiration, less energy released so less metabolism.

42
Q

What is a tissue?

A

A group of similar cells working together for a particular function

43
Q

What is the issue with excess fat in the body?

A
  • Can cause CHD as can cause cholesterol to build up in coronaries so may need a statin/stent
  • Can lead to obesity which is a risk factor for type 2 diabetes
44
Q

What is the use of fibre?

A

Aids digestion

45
Q

How are stomata adapted?

A
  • Open wider at a greater light intensity to take in more CO2 for photosynthesis
  • Get narrower at night in lower light intensity to reduce water loss
    (due to guard cells)
46
Q

Define double circulatory system

A

Deoxygenated blood pumped from right ventricle to lungs for gas exchange. Oxygenated blood pumped from left ventricle to entire body. Improves efficiency.

47
Q

Describe the function of the phloem

A

Transports dissolved sugars up and down plant from the leaves from photosynthesis for immediate use or for storage

48
Q

Explain 3 differences between arteries and valves

A
  • arteries have thicker muscle layers
  • arteries have a narrower lumen
  • veins have valves, arteries don’t

Biology 1 (4 decks)

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