B2 Flashcards

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1
Q

Molecules too big to pass through the walls of the digestive system

A

Starch, proteins, fats

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2
Q

Molecules that can pass through the walls of the digestive system

A

Sugars, amino acids, glycerol and fatty acids

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3
Q

What are carbohydrases?

A

Digestive enzymes that break down starch to sugars

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4
Q

What are proteases?

A

Digestive enzymes that digest proteins to amino acids

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5
Q

Lipase?

A

Digests fat into fatty acids and glycerol

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6
Q

Mouth

A

Food is moistened with saliva from to salivary glands
They produce amylase
Food is chewed to form a bonus

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7
Q

Oesophagus

A

A tube that takes food from the mouth to the stomach. It’s lined with muscles that contract to help the ball of food move along by peristalsis

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8
Q

Liver

A

Where bile is produced

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9
Q

Bile

A

Neutralises stomach acid and emulsifies fats

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10
Q

Gall bladder

A

Where bile is stored

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11
Q

Stomach

A

Pummels the food
Produces Pepsin
Hydrochloric acid

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12
Q

Why does the stomach produce hydrochloric acid

A

To kill bacteria

To give the right pH for the protease enzyme

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13
Q

Pancreas

A

Produces protease, amylase, and lipase enzymes, it releases these into the small intestine

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14
Q

Small intestine

A

Produces protease, amylase and lipase enzymes to complete digestion.
This is where the food is absorbed out into the body

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15
Q

Large intestine

A

Where excess water is absorbed from the food

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16
Q

Osmosis

A

The movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration

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17
Q

Root hairs take in water by which process

A

Osmosis

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18
Q

Root hairs take in minerals by which process

A

Active transport

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19
Q

How does active transport work

A

Because the concentration of minerals in the soil is pretty low, it uses energy from respiration to help the plant pull minerals into the root hair against the concentration gradient

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20
Q

Xylem tubes

A

Transport water and minerals from the root to the rest of the plant

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21
Q

Phloem tubes

A

Transport sugars from the leaves to growing and storage tissues

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22
Q

Transpiration.

A

The loss of water from a plant

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23
Q

Digestion

A

The breakdown of food into soluble products which are then absorbed into the body

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24
Q

Chromosomal DNA

A

One long circular chromosome

Controls the cells activities and replication

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25
Q

Plasmids

A

Small loops of extra DNA that aren’t part of the chromosome

Contain genes for things like drug resistance and can be passed between bacteria

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26
Q

Flagellum

A

Rotates to make the bacterium move

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27
Q

What are the base pairs

A

Adenine- Thymine

Guanine- Cytosine

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28
Q

Who discovered the structure of DNA

A

Watson, Crick, Franklin and Wilkins

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29
Q

Transcription

A

The DNA strands unzip
The DNA is used as a template for the mRNA
Base pairing ensures its complimentary

30
Q

Translation

A
  • mRNA moves out of the nucleus and joins with a ribosome
  • Amino acids that match the base codons are brought to the ribosome by tRNA
  • The ribosome attaches the amino acids together in a Polypeptide chain (protein)
  • This then folds up into the right shape to do a specific job eg. Enzyme
31
Q

Mutations

A

Change to an organisms DNA base sequence

Can be harmful- genetic disorder
Or beneficial- new characteristic- antibiotic resistance

32
Q

Genetic engineering

A

Useful gene is cut out of the human DNA using restriction enzymes

The restriction enzymes cut the bacterial DNA and put in the useful human gene

33
Q

Uses for genetic engineering

A
  • Reducing vitamin A deficiency-rice produce beta carotene
  • Producing human insulin
  • Increasing crop yield-resistant to herbicides
34
Q

Problems with genetic engineering

A
  • Reduce farmland diversity
  • Transplanted genes could get out to the natural environment eg. Weeds
  • People may develop allergies
35
Q

Enzymes

A

Biological catalysts which reduce the need for high temperatures
They are all proteins
Can work inside or outside cells

36
Q

How to enzymes react to heat

A

Rate of reaction increases with heat until the optimum temperature
After which they are denatured

37
Q

How to enzymes react to pH

A

Enzyme denatures if the pH is too high or too low

Peaks at the optimum pH

38
Q

How to enzymes speed of reactions change with substrate concentration?

A

Increases until there are not enough enzymes

39
Q

Human genome project

A

Thousands of scientists collaborated to find every single human gene

40
Q

Benefits to the human genome project

A
  • Predict and prevent diseases
  • Develop new and better medicines
  • Accurate diagnosis
  • Improve forensic science
41
Q

Problems with the human genome project

A
  • Increases stress- If people know they’re suspect to a brain disease they may panic at small things like headaches
  • People with genetic problems could be under pressure not to have children
  • Discrimination by employers and insurers
42
Q

Respiration

A

The process of breaking down Glucose to release energy which goes on in every living cell

43
Q

Cloning mammals

A
Nucleus removed from an egg cell 
Adult diploid cell nucleus placed in 
Electric shock 
Embryo starts to develop 
Implanted into surrogate mother
44
Q

Uses of cloning

A
  • Help meet the demand for organ transplants
  • Greater understanding of the embryo, ageing and age related disorders
  • Preserve endangered species
45
Q

Issues with cloning

A
  • Reduced Gene pool
  • Cloned mammals mightn’t live as long
  • Cloning often fails
  • Clones are often born with genetic defects
  • Clones immune systems are sometimes unhealthy
46
Q

Stem cell uses

A
  • Bone marrow transplant to cure sickle cell anaemia

- May be possible to create specialist cells to replace those that have been damaged

47
Q

Problems with stem cells

A
  • First a lot of research must be done
  • Ethical concerns such as
  • it is potentially a human life
  • the people who are suffering are more important and the ones used are unwanted from fertility clinics
  • In some countries stem cell research is banned
48
Q

Anaerobic respiration

A

Glucose to lactic acid

Doesn’t release as much energy, build up of lactic acid causes cramp

When the body can’t supply oxygen to the muscles fast enough

49
Q

EPOC

A

Excess Post-exercise Oxygen Consumption

50
Q

What happens when you exercise

A
  • Your muscles contract more than normal so they need more energy
  • Your breathing rate increases and your heart rate increases
  • The rate of diffusion of CO2 and O2 at lung surface and in muscle cells increases
51
Q

What are the three ways fossils can be formed

A
  • Gradual replacements by minerals
  • Casts and impressions- material around it hardens
  • Preservation eg. glaciers and Amber
52
Q

Why is the fossil record incomplete

A
  • Few dead plants and animals actually turn into fossils
  • Some body parts decay away completely
  • There are fossils left to be discovered
53
Q

What do fossils tell us

A
  • What creatures and planes looked like
  • How long ago they existed
  • How they’ve evolved
54
Q

Pentadactyl limb

A
  • A limb with 5 digits
  • You can see it in many species
  • The similarity suggests species with the pentadactyl limb evolved from a common ancestor
55
Q

Left side of the heart

A

Oxygenated blood to body

Pulmonary vein
Left atrium
Left ventricle
Aorta

56
Q

Right side of the heart

A

Deoxygenated blood to lungs

Vena carva
Right atrium
Right ventricle
Pulmonary artery

57
Q

Functional foods

A

A food that has some kind of health benefit beyond basic nutrition

58
Q

Probiotics

A

Contain live bacteria to help keep your digestive system healthy and your immune system strong

59
Q

Prebiotics

A

Contain carbohydrates we can’t digest

Promote growth of good bacteria for digestive and immune system

60
Q

Plant Stanol Esters

A

Chemicals that lower blood cholesterol and reduce risk of heart disease

61
Q

Why does bile emulsify fats?

A

Breaks the fat into tiny droplets giving it a much larger surface area and so the lipase digests it faster

62
Q

What are villi and why are they helpful?

A

Inside the small intestine

  • Have a big surface area so that digested food is absorbed more quickly into the blood
  • Single layer of surface cells so that digested food diffuses quickly
  • Good blood supply via capillary network to assist quick absorption of digested food
63
Q

Arteries

A

Carry blood away from heart at high pressure

  • Walls are strong and elastic
  • Thick walls compared to lumen
  • Thick layers of muscle
64
Q

Capillaries

A

Carry blood really close to every cell to exchange substances with them

  • Permeable walls
  • Supply oxygen and take away CO2
  • Walls are one cell thick increasing the rate of diffusion by decreasing the distance over which it occurs
65
Q

Veins

A

Take blood back to the heart

  • Lower pressure so walls aren’t as thick as arteries
  • Bigger lumen to help flow despite lower pressure
  • Valves to keep blood flowing in the right direction
66
Q

Red blood cells

A

Carry oxygen

  • Biconcave disc for a large surface area
  • Contain haemoglobin (contains lots of iron)
  • Don’t have a nucleus
67
Q

White blood cells

A
  • Change shape to consume unwelcome microorganisms
  • Produce antibodies to fight microorganisms
  • Produce antitoxins to neutralise any toxins produced by microorganisms
68
Q

Too many or too little white blood cells

A

Can increase the risk of infection

Or mean you have an infection or Leukaemia

69
Q

Platelets

A
  • Small fragments of cells
  • Help blood to clot at a wound
  • Lack of platelets means excessive bleeding or bruising
70
Q

Plasma

A

Pale yellow liquid that keeps the blood fluid and transports everything

  • Red, White blood cells, Platelets
  • Nutrients like Glucose and Amino acids
  • Carbon dioxide
  • Urea
  • Hormones
  • Antibodies/ Antitoxins
71
Q

Transpiration

A
  • Caused by evaporation and diffusion of water from inside the leaves
  • Creates a shortage of water so more is drawn up
  • Constant transpiration stream of water