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BMAT > Bio > Flashcards

Bio Flashcards

1
Q

Plasmid DNA

A

double-stranded

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2
Q

RBC shape

A

Biconcave

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3
Q

Palisade mesophyll shaker

A

columnar

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4
Q

Cell membrane

A

Flexible

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5
Q

Examples of diffusion in living systems - 7

A

gas exchange in the lungs (oxygen and carbon dioxide)

absorption and release of oxygen by red blood cells

absorption of solutes into the blood stream from the kidney tubules

absorption of digested food molecules into the blood stream from the ileum

movement of neurotransmitter substances across synaptic gap in the nervous system

absorption of carbon dioxide by palisade mesophyll cells in a leaf

loss of water vapour from plant leaves during transpiration.

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6
Q

Examples of osmosis - 7

A

Plants rely on osmosis to obtain water through their roots. Water is transferred from cell to cell by osmosis.

When plant cells are turgid, their rigidity can keep the whole plant firm and upright. Leaves can be held in the best position possible to trap (absorb) sunlight for photosynthesis.

When plant cells are flaccid, they lose their rigidity and the whole plant can wilt.

If animal cells are exposed to pure water, they can swell up and burst (in a red blood cell this is called haemolysis). Red blood cells, for example, would not then be able to carry oxygen.

If animal cells lose water, they become flaccid. Red blood cells, for example, would be less efficient at carrying oxygen.

Water is absorbed by osmosis from the ileum and colon as food passes along the alimentary canal.

Water is reabsorbed in the kidney tubules by osmosis.

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7
Q

Examples of active transport - 2

A

Plant root hair cells use active transport to move mineral salts from the soil into the root. These salts are commonly in lower concentrations in soil than in the plant root cells, so diffusion is not adequate to absorb them.

Glucose is moved from the small intestine into the blood stream of mammals by active transport. Absorption of glucose by diffusion would stop once the concentration in the blood reached that of the intestine.

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8
Q

Zygote

A

fertilised egg cell

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9
Q

Asexual reproduction:

A

requires only one parent
and
there is no production or fusion of gametes.

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10
Q

Binary fission

A

produces a copy of the loop of chromosomal DNA found in the cell’s cytoplasm.

The cell then divides into two, passing one copy of the chromosomal DNA to each new daughter cell.

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11
Q

Importance of producing genetically different offspring - 3

A

Genetic variation is essential for natural selection.

Natural selection enables populations of organisms to adapt to changes in the environment. It ensures the successful continuation of a species over time.

helps to reduce the frequency with which recessive inherited conditions occur.

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12
Q

What is smaller X or Y chromosome

A

Y

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13
Q

Sex chromosomes in gametes?

A

Each human sperm contains 23 chromosomes, one of which is a sex chromosome (either an X or a Y).

Each human ovum contains 23 chromosomes, one of which is always an X chromosome.

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14
Q

Punnett square diagram - Probability showing gender ratio

A
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15
Q

chromosome

A

long thread-like structure made of DNA which is wrapped around proteins.

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16
Q

Genotype

A

alleles we have that control a characteristic are called our genotype.

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17
Q

Cystic fibrosis

A

caused by the recessive allele, f.

The condition affects chloride ion transport across membranes, resulting in thick, sticky mucus.

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18
Q

Arrange the following terms in order of size, from smallest to largest:
base
DNA molecule
gene
nucleotide
triplet

A

Base, nucleotide, triplet, gene, DNA molecule

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19
Q

Silent mutation example

A

when the mutation changes one of the bases in the triplet but the triplet still codes for the same amino acid.

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20
Q

GMO

A

genetically modified organism or a transgenic organism.

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21
Q

Process of genetic engineering

A
  • useful gene cut from DNA of one organism using restriction enzymes
  • restriction enzymes cut DNA in staggered way (sticky ends)

-bacterial plasmid DNA cut open using dame restriction enzymes (sticky ends are complementary)

  • useful gene and the plasmid DNA are mixed and the gene is inserted into the plasmid.+ hydrogen bonds form

-enzyme DNA ligase is used to join the plasmid DNA and the useful gene

  • recombinant plasmid is then inserted into a bacterial cell
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22
Q

Restriction enzymes

A

breaks bonds between nucleotides.

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23
Q

enzyme DNA Ligase

A

joins the end nucleotides of the useful gene to the end nucleotides of the plasmid.

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24
Q

What is the modified plasmid called

A

recombinant plasmid

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25
Q

What does the bacteria cell act as now

A

Vector

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26
Q

Type of protein produced by genetically modified bacteria - hormones

A

Insulin

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27
Q

Type of protein produced by genetically modified bacteria - antibiotics

A

Penicillin

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28
Q

Type of protein produced by genetically modified bacteria -enzymes

A

Rennin

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29
Q

Type of protein produced by genetically modified bacteria - blood clotting factors

A

Factor VIII

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30
Q

Why is technique to genetically modify plant cells is different to that used to create GM bacteria

A

plant cells do not have plasmids.

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31
Q

Genetically modify plants process

A
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32
Q

Characteristics of GM plants

A

pest resistance

herbicide resistance

disease resistance

ability to produce nutrients to help prevent malnutrition

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33
Q

pest resistance

A

Bt cotton is resistant to cotton bollworm, a pest that destroys cotton crops

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34
Q

herbicide resistance

A

GM crops resistant to weedkillers such as glyphosate-resistant soybean

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35
Q

disease resistance

A

bananas modified to resist the black sigatoka fungus

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36
Q

ability to produce nutrients to help prevent malnutrition

A

golden rice is a plant that has been modified so that it has an increased level of ß-carotene, in order to help prevent vitamin A deficiency

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37
Q

Benefits of genetic engineering in medicine

A
  • GMOs used to produce medicine
  • GMOs have been used in the development of vaccines.
  • GM pigs are being developed with human-like organs.
  • GM insects have been created to reduce the spread of certain diseases such as malaria.

-Genetic modification of cells in the human body can be carried out using gene therapy techniques to provide possible cures for genetic diseases such as cystic fibrosis.

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38
Q

GMOs can be used to produce medicines.
- examples

A

e.g. GM bacteria produce the human insulin protein which is used to treat diabetes.

e.g. GM sheep produce proteins in their milk that are used to treat lung disease.

e.g. GM cells grown in culture produce proteins such as human blood clotting factor VIII to treat haemophilia, an inherited condition that means a person’s blood does not clot if they cut themselves because they are unable to produce this clotting factor.

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39
Q

GMOs can be used to produce medicines. Good + bad

A

Good - larger quantities produced / less rejection

Bad - unknown side effects

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40
Q

GMOs have been used in the development of vaccines… examples

A

e.g. a recombinant hepatitis B vaccine produced by GM baker’s yeast.

e.g. GM plants are being developed with the aim of providing edible vaccines.

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41
Q

Genetic modification of cells in the human body can be carried out using gene therapy techniques to provide possible cures for genetic diseases such as cystic fibrosis. - risks

A
  • cancer
  • unable to control the position where it is inserted
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42
Q

Examples of GM stem cells treatment

A

Sickle cell anaemia affects the production of haemoglobin proteins. Red blood cells carry haemoglobin molecules with a slightly altered shape which are unable to transport oxygen as efficiently.

GM bone marrow cells could be used to create red blood cells that carry haemoglobin proteins with a shape that is better able to transport oxygen.

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43
Q

Aims of sickle cell anaemia treatment

A

provide a longer-term cure as the GM stem cells will continually generate healthy red blood cells

remove the need to find a suitable donor to provide stem cells as stem cells from the patient can be used

remove the risk of rejection of donor cells.

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44
Q

Zygote divides by

A

Mitosis

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45
Q

Stem cells that occur in early stages of life

A

Totipotent - differentiate and develop into any of the wide variety of specialised cells found in an adult human.

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46
Q

Difference between pluripotent and totipotent

A

pluripotent cells cannot produce the cells that will become the placenta.

Only totipotent cells can do this.

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47
Q

Examples of how embryonic stem cells could be used

A

treating diabetes by replacing insulin-secreting cells in the pancreas

treating burns by replacing damaged skin tissue

replacing neurones damaged by spinal cord injury

replacing cells in the heart damaged by a heart attack

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48
Q

induced pluripotent stem cells (iPSC)

A

cells that have been produced in the laboratory using adult body cells.

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49
Q

Benefits of iPSC

A

the treatment of conditions in place of the more controversial embryonic stem cells

stem cells produced from a patient’s own body cells should not be rejected as foreign

learning more about specific diseases by culturing cells from a patient in the laboratory and then inducing them to differentiate into a specific cell type which can be studied, e.g. brain cells cultured to learn more about Alzheimer’s disease which affects the brain

testing the effectiveness of drugs in cell culture before they are used in a patient.

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50
Q

Domesticated animals rely on…

A

humans for survival

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51
Q

How selective breeding works

A

Animals with desirable characteristics, e.g. rapid growth rate, are selected for breeding.

↓

These animals are bred together.

↓

The animals with the most desirable characteristics are selected from the offspring.

↓

These offspring animals are then bred together.

↓

This cycle is repeated over many generations.

↓

Over time the desirable characteristic starts to increase in the population, e.g. animals which have a higher and higher growth rate.

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52
Q

Why does selective breeding increase chance if genetic disorders

A

alleles that cause genetic conditions are often recessive.

If genetic variation is low in a population, there is an increased chance of animals being homozygous recessive and therefore developing an inherited condition

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53
Q

hydrolysis

A

broken by the addition of water

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54
Q

condensation reaction

A

formed by the removal of water

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55
Q

Why does the rate of reaction decrease when conditions move away from optimum

A

a reduction in energy available for the reaction

the bonds holding the enzyme in a specific 3D shape have been broken = denatured

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56
Q

Characteristics of extreme habitat conditions

A

extreme pressure

high sodium chloride levels

high levels of various metals

low water availability.

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57
Q

Amylase

A

Breaks down starch into maltose / glucose

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58
Q

Where are extracellular enzymes produced

A

specialised cells in glands and tissues

e.g. salivary glands, stomach lining, pancreas, intestinal lining.

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59
Q

Where are extracellular enzymes secreted fro,

A

mouth, stomach or small intestine

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60
Q

commercial uses of enzymes

A
  • pre digest baby food
  • biological washing powders = get rid of stains
  • production of sugar syrups
  • manufacturing pharmaceuticals
  • making ethanol from plants
  • wine and beer production.
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61
Q

Why are the digestive enzymes of a human extracellular?

A

The molecules are too big to cross the membrane into the cells for digestion. Therefore enzymes need to be secreted into the gut to digest these molecules so their products can be absorbed and then used by cells.

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62
Q

Energy from respiration used for

A

protein synthesis and making other new molecules

active transport

cell division

muscle contraction.

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63
Q

Where does aerobic respiration happen in eukaryotic + prokaryotic

A

Eukaryotic - mitochondria

Prokaryotic - cytoplasm

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64
Q

Where does anaerobic respiration happen

A

Cytoplasm

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65
Q

After exercise the breathing rate may remain high. Why

A

Extra oxygen taken in during this period is used to replenish the oxygen debt required to remove any toxic lactic acid from the body.

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66
Q

What does oxygen do to lactic acid

A

Oxidise it

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67
Q

Is respiration effected by changes in temp

A

YES - ENZYME CATALYSED = DENATURED

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68
Q

Lactic acid

A

Lowers pH

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69
Q

What is the nervous system

A

rapid communication system in the bodies of animals.

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70
Q

Nerves

A

made of bundles of the axons of neurones.

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71
Q

Is the spine in the nervous system

A

NO = SPINAL CHORD

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72
Q

What is a neurone?

A

Nerve cell

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73
Q

Function of a neurone

A

transmit electrical impulses

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74
Q

Basic structure of neurone

A

contain a single nucleus in their cell body, and extensions of their cytoplasm that allow electrical impulses to travel through them.

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75
Q

Types of neurone 3

A

sensory, relay and motor neurones.

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76
Q

Sensory

A

connect receptors, which detect stimuli in the environment, with the central nervous system.

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77
Q

Relay

A

found within the central nervous system.

These connect the sensory as well as motor neurones and allow communication to and from the brain.

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78
Q

Motor

A

connect the central nervous system to effectors.

These are the parts of the body that produce a response to the electrical impulse.

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79
Q

Effectors

A

muscles and glands.

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80
Q

Structure of sensory

A
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81
Q

Structure of relay

A
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82
Q

Structure of motor

A
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83
Q

Axon

A

long section of the neurone through which an electrical impulse can travel

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84
Q

What is axon surrounded by

A

Myelin sheath

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85
Q

Function of myelin sheath

A

protects the axon and makes the impulse travel faster.

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86
Q

Function of dendrites

A

allow them to make connections to other neurones.

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87
Q

Which neurones have a myelin sheath

A

Motor + sensory

NOT RELAY

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88
Q

How big is a synapse

A

1 µm

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89
Q

What is a synapse

A

small gap between two neurones

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90
Q

Function of synapses

A

allow neurones to transmit electrical impulses to each other.

They also allow multiple neurones to connect with each other at once. These connections are made between the dendrites of different neurones.

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91
Q

How do impulses cross a synapse?

A

electrical impulse travels along the axon of a neurone until it reaches the end of the neurone.

Impulse causes a chemical to be released into the synapse = neurotransmitter

It diffuses from the axon across the synapse to the neurone on the other side.

When it reaches the surface of the dendrite, it binds to a receptor which allows the electrical impulse to be regenerated.

This new impulse then travels down the axon of the other neurone. This process happens very quickly.

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92
Q

Draw out synapse

A
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93
Q

Neurotransmitters are..

A

CHEMICALS

NOT ELECTRICAL UMOUKSESN

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94
Q

Reflex arc pathway

A
  • stimulus
  • receptor generates electrical impulse
  • passed to sensory neurone
  • goes along axon of sensory neurone to spinal chord
  • crosses a synapse using chemical messengers
  • produces impulse in relay neurone in CNS
  • connects via other synapse to motor neurone
  • effector
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95
Q

Structure of respiratory system

A
  • found in thorax (chest)
  • air enters through nose / mouth
  • through larynx = voice box
  • then trachea
  • then one bronchi / bronchus
  • then bronchioles
  • then alveoli
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96
Q

What contains cartilage

A

Trachea + bronchi + bronchioles

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97
Q

Features of air entering body

A
  • more oxygen
  • less carbon dioxide
  • less water Vapour
  • pollen / dust / virus
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98
Q

Features of air leaving body

A
  • less oxygen
  • more carbon dioxide
  • more water vapour
  • cleaner
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99
Q

How is the air that enters the body cleaned

A

cleaned as it passes through the bronchi.

The cells lining the bronchi produce mucus to trap any particles in the inhaled air.

This includes pollen, dust, bacteria and viruses.

Small hairs, called cilia, on the cells then move the mucus up to the top of the trachea where it can be swallowed into the acid contents of the stomach in the digestive system.

This destroys them and then they are removed from the body.

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100
Q

If cilia paralysed by cooking

A

More dust could be present in exhaled air.

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101
Q

Normal exhalation

A

passive - uses only the diaphragm and intercostal muscles to expel air

102
Q

Forced exhalation

A

Active

103
Q

Why is forced exhalation active

A

muscles of the abdominal wall can also contract.

104
Q

Breathing in

A

ICC

rib cage move up and out

105
Q

Breathing out

A

ORR

ribs down and inwards.

106
Q

How is the body adapted to allow efficient gas exchange?

A

The alveoli have a large surface area across which diffusion can occur.

There are thousands of alveoli in each lung, increasing the surface for diffusion further.

The alveoli and capillary walls are only one cell thick to ensure that the diffusion distance is short.

The capillaries are wrapped around the alveoli, reducing the distance that the gases must diffuse.

Blood constantly flows through the capillaries. This maintains the concentration gradients of each gas. This makes sure that both gases diffuse rapidly and in the correct direction.

107
Q

Kidneys

A

Renal

108
Q

How to read ECG

A
109
Q
A

W = stimulates the atria to contract, forcing blood out of the atria and into the ventricles.

X = stimulates the ventricles to contract, which will force blood out of the ventricles into the aorta and pulmonary artery.

110
Q

Most common components of blood = in healthy person = red blood cells, white blood cells and platelets

A

In a healthy person, red blood cells are most numerous and the white blood cells are the least numerous.

111
Q

What does plasma contain

A

dissolved glucose, urea and amino acids, as well as most of the carbon dioxide and some proteins like hormones and antibodies.

112
Q

How much does plasma make up

A

Plasma makes up 55% of the volume of blood.

113
Q

Two types of white blood cell

A

lymphocytes and the phagocytes

114
Q

Lymphocytes

A

produce antibodies

Memory cells

115
Q

Phagocytes

A

Engulf pathogens

116
Q

Structure of phagocyte

A

Lobed nucleus

117
Q

Structure of lymphocyte

A

Large nucleus

118
Q

Platelets

A

small fragments of cells

No nucleus

119
Q

Clotting

A

Enzymes convert a soluble protein called fibrinogen into the insoluble fibrin.

This creates a mesh of fibres that traps platelets and red blood cells, forming the clot.

120
Q

ABO system

A

In humans one of the blood group systems is known as the ABO system.

The gene for the ABO system codes for a protein found on the cell surface membrane of red blood cells.

This protein is called an immunoglobulin (I).

121
Q

Blood group table

A
122
Q

Blood group + antibodies present in plasma

A
123
Q

Blood group = donate = receive

A
124
Q

Which component of blood contains DNA

A

Inky WBC

rBC + platelets = NOnucleus

125
Q

Which component of blood Requires proteins in order to perform its function

A

White blood cells which need antibodies and enzymes, red blood cells which need haemoglobin and platelets which need fibrinogen/fibrin.

All of these are proteins.

126
Q

Could help protect the body from a bacterial infection.

A

White blood cells and platelets. White blood cells can produce antibodies to kill bacteria or ingest and digest them. Platelets form clots at wound sites to stop bacteria entering and infecting the body.

127
Q

Overall functions of digestive system

A

the breakdown of large insoluble molecules found in food into their soluble products

the absorption of these products of digestion.

128
Q

Food passes through the digestive system in the following order:

A

1) mouth

2) oesophagus

3) stomach

4) small intestine

5) large intestine.

129
Q

How is food moved through digestive system

A

peristalsis

130
Q

What is peristalsis

A

waves of muscular contraction that move the bolus (ball of food) along.

131
Q

two types of digestion:

A

mechanical – teeth grinding, stomach churning

chemical – using bile and enzymes which are produced by specialised cells in glands and tissues in the gut lining.

132
Q

Purpose of HCl

A

kills bacteria and provides the correct pH for the protease enzyme to digest protein.

133
Q

Purpose of bile + pancreatic juice

A

contain hydrogen carbonate (bicarbonate) ions to neutralise the stomach acid when it enters the small intestine and provide the alkaline conditions needed by the enzymes present in the small intestine.

134
Q

path of nutrients through the different parts of the digestive system + the glands associated with the digestive system

A

Order 1-5

135
Q

Bile - made + stores

A

Bile is made in the liver and stored in the gall bladder

136
Q

Purpose of bile

A

released into the small intestine when stomach contents arrive in the small intestine.

It emulsifies lipids to increase the surface area for lipases to work on and therefore the rate of digestion is increased.

137
Q

Food contains many large molecules that need to be digested

A

Starch, protein, lipids = large insoluble molecules – cannot pass through the gut wall.

Extracellular enzymes are secreted into the gut lumen to break down the large insoluble molecules in food by hydrolysis.

Fibre cannot be digested and absorbed in humans as the enzymes required are not present.

138
Q

What can’t be digested in humans

A

Fibre

139
Q

Products of digestion

Glucose, amino acids:

A

small soluble molecules – pass through the gut wall and are absorbed into the blood.

140
Q

Products of digestion

Glycerol, fatty acids:

A

small soluble molecules – pass through the gut wall and into the lymph system before entering the blood.

141
Q

main site of absorption

A

Small intestine

142
Q

Structure of small intestine

A

The wall of the small intestine contains millions of finger-like projections called villi that increase the surface area.

Villi contain many blood capillaries so that there is an excellent blood supply to carry away the products of digestion as soon as they have been absorbed.

The flow of blood maintains a steep concentration gradient so that diffusion is as rapid and efficient as possible.

143
Q

Absorbed nutrients are used by body cells:

A

to make new macromolecules – carbohydrates, proteins, lipids

in aerobic respiration.

144
Q

Where is glycogen stored

A

liver and muscle cells.

145
Q

undigested waste matter colour

A

The brown colour of the faeces is due to bile pigments.

146
Q

Where do faeces go

A

pass through the large intestine and into the rectum.

They are then expelled through the anus in a process known as egestion.

147
Q

Why is it necessary to have an amylase in the mouth and another one secreted by the pancreas?

A

Change in pH

148
Q

Organs involved in excretion

A

liver, lungs, skin and kidneys.

149
Q

What does the liver break down

A
  • amino acids = deamination = Nitrogen converted into = urea
  • haemoglobin from red blood cells = forms yellow/green bile pigment called bilirubin
150
Q

What happens to yellow/green bile pigment called bilirubin

A

excreted with bile into the small intestine.
Bilirubin is expelled with faeces.

151
Q

Why is the lungs an excretory organ

A

remove carbon dioxide

152
Q

Why is the skin an excretory organ

A

produces sweat, which consists of sodium chloride and traces of urea dissolved in wate

153
Q

Why is the skin different to kidneys / lungs

A

Sweating could be considered to be an excretory process, but it is not a response to changes in blood composition so skin is not an excretory organ in the same sense as the lungs or kidneys.

154
Q

Roles of kidney - 3

A

the removal of urea

adjustment of the ion content

adjustment of the water content.

155
Q

Draw out kidney area

A
156
Q

What controls the release of urine through the urethra.

A

A sphincter muscle at the base of the bladder

157
Q

Draw structure of kidney

A
158
Q

Structure of nephron

A

glomerulus, renal capsule and renal tubule.

159
Q

Three main regions of kidney

A

cortex, medulla and pelvis.

160
Q

Structure of kidney / nephron - words

A

Blood enters a kidney through a renal artery.

This divides into arterioles and capillaries in the cortex.

Each capillary becomes knotted to form a glomerulus, which is surrounded by a Bowman’s capsule.

This leads to a convoluted tubule. The proximal convoluted tubule passes down into the medulla, where it forms the loop of Henle, returning to a distal convoluted tubule in the cortex again.

The tubule joins a collecting duct, which passes down through the medulla into the pelvis of the kidney

161
Q

How the nephron functions = whole thing

A
  • wall of the capillary of the glomerulus acts as a filter.
  • blood enters the glomerulus, its pressure increases.
  • Large structures (blood cells) and large molecules, e.g. plasma proteins, are retained within the capillary, but smaller molecules (water, dissolved salts (ions), glucose and urea) are forced out by ultrafiltration.
  • This is filtration under pressure.
  • The filtrate is collected by the renal capsule and passes into the renal tubule.
  • As the filtrate passes along the tubule, selective reabsorption takes place into the capillaries surrounding the tubule.
  • Glucose is reabsorbed by diffusion and active transport.
  • Water is reabsorbed by osmosis, along with some salts by diffusion and active transport to maintain the correct concentration in the blood.
  • Salts not needed by the body, along with urea and uric acid, continue along the tubule into a collecting duct in the medulla.
  • The collecting duct delivers the filtrate to the pelvis of the kidney, where the fluid (urine) passes into a ureter to transfer it to the bladder for storage.
  • Urine is retained in the bladder by a sphincter muscle at its base.
  • When the sphincter muscle relaxes, the muscle wall of the bladder contracts to expel the urine (a process called urination) through the urethra.
162
Q

Sweat + urine

A

On a cold day, less sweating occurs. This means that less water is lost in sweat. The kidneys respond by producing a larger volume of less concentrated urine.

163
Q

How will the composition of blood leaving a kidney be different from the composition of blood entering it?

A

less water, fewer salts, less urea and less uric acid than blood entering the kidney + more CO2

The cells of the kidney carry out aerobic respiration so will require oxygen and will produce carbon dioxide. Therefore the blood leaving the kidney will have a higher carbon dioxide concentration and a lower oxygen concentration than the blood entering the kidney.

164
Q

Ureter vs urethra

A

The ureter carries urine from the kidney to the bladder. The urethra carries urine from the bladder to be expelled from the body.

165
Q

Response to high temp

A
  • detected by thermoregulatory system in brain
  • nerve impulses sent to skin
  • arteries dilate - vasodilation
  • sweat glands secrete more sweat
166
Q

Responding to an increase in blood glucose levels

A
  • islet cells of the pancreas detect the change and secrete insulin in response.
  • insulin is transported to the liver in the blood plasma
  • stimulates liver cells to take up the glucose from the blood and convert it to glycogen.
  • stimulates other body cells to take up more glucose for use in respiration.
167
Q

Responding to a decrease in blood glucose levels

A
  • islet cells = glucagon
  • transported by the blood plasma to the liver
    causing them to convert stored glycogen back to glucose to raise blood glucose levels.
168
Q

Type 1 diabetes

A
  • inability of the pancreatic islet cells to secrete enough insulin
  • inherited / virus / autoimmune
169
Q

Water gains vs loses

A
170
Q

High levels of ADH…

A

cause the kidneys to reabsorb more water, so less urine is excreted, e.g. on a hot day or during exercise.

171
Q

How does ADH work

A

binds to the collecting ducts of the nephrons making them more permeable to water. The water leaves the ducts and re-enters the blood.

172
Q

ADH cycle

A
173
Q

What detects water levels

A

Hypothalamus - causes pituitary to release ADH

174
Q

Too cold

A
  • skeletal muscles contract involuntarily
  • hair erector muscles to contract = insulates heat
175
Q

Thyroxine released from

A

thyroid gland

176
Q

Role of thyroxine

A

regulating the basal metabolic rate

177
Q

Too high thyroxine in blood

A

Monitored by hypothalamus

release of TSH by the pituitary gland is inhibited.

Less thyroxine is released from the thyroid gland.

The level of thyroxine in the blood falls to within the normal range.

178
Q

Explain why blood thyroxine levels continue to rise after TSH is inhibited.

A

some TSH would still be present in the blood so the thyroid gland would continue to be stimulated to release thyroxine until TSH blood levels were reduced. As this takes time, the blood thyroxine levels would initially continue to rise.

179
Q

Effect of adrenaline

A
180
Q

Why are nervous impulses used to stimulate the adrenal glands to release adrenaline in this case, instead of hormones?

A

Hormones are slow acting so the response would take time to occur, which might put the body in danger.

181
Q

Describe graph

A

FSH is produced by the pituitary gland and acts on target structures in the ovaries.
FSH stimulates an ovary:
- to develop a follicle containing an egg (ovum maturation)
- to produce oestrogen.

Oestrogen is produced by the ovaries
- stimulates the uterus lining to thicken.

LH is produced by the pituitary gland and acts on target structures in the ovary
- stimulates the mature follicle to release the egg/ovum (ovulation) in the middle of the cycle (around day 14).

Progesterone is secreted by the empty follicle in the ovary (the yellow body or corpus luteum)
- maintains the lining of the uterus during the second half of the cycle so that a fertilised egg may implant.

Oestrogen and progesterone inhibit the production of LH and FSH.

Decreasing progesterone levels cause the thickened uterus lining to break down and be discharged (menstruation).

182
Q

Oral pill – two types:

A

combined oestrogen and progesterone
progesterone only.

183
Q

retrovirus (HIV)

A

contains RNA as its genetic material and has an enzyme called reverse transcriptase = catalyses the conversion of viral RNA to DNA.

184
Q

reverse transcriptase.

A

only found in retroviruses

185
Q

HIV target

A

Lymphocytes

186
Q

anti-retroviral drugs.

A

stop reverse transcriptase from functioning = no new HIV

187
Q

Spread of flu

A

airborne droplets of sputum sneezed or coughed out of an infected person and inhaled by an uninfected person. + contact

188
Q

Spread of TMV

A

by direct contact, or via an insect such as an aphid

189
Q

Protists

A

single-celled organisms that have a nucleus.

E,g Plasmodium is a protist that causes malaria.

190
Q

ways to prevent malaria

A
  • sleeping inside mosquito nets
  • skin lotions = repelling chemicals
  • anti-malarial medicine before going to malaria infected areas
191
Q

Ways of interrupting the mosquito life cycle include:

A

adding fish to the water that eat the larvae
draining areas of stagnant water.

192
Q

Fungus reproduce

A

spores asexually

193
Q

How does a vaccine work

A
194
Q

What is the difference between being ‘immune’ and being ‘resistant’?

A
  • person has previously been exposed to a pathogen with its specific antigens and the person has made memory cells.
  • individual has either received a gene for resistance from one or both parents, or a mutation has occurred in their DNA leading to resistance
195
Q

Can immunity be passed down

A

No

196
Q

Can resistance be passed down

A

Yes

197
Q

Sequence of new medicine testing

A
198
Q

If the chemical being tested does work

A

its positive effect should be greater than the placebo effect.

199
Q

Coronary heart disease

A
  • coronary arteries = blocked
  • cells die = no glucose / oxygen
  • blockage is usually either a fatty deposit called atheroma, or a blood clot.
200
Q

risk factors that can be modified:

A

diet – consumption of foods high in fat/cholesterol increase risk of atheroma; and a high salt intake increases the risk of

hypertension

too little exercise

obesity

smoking

excess alcohol intake.

201
Q

Life long medication for CVD

A

Statins

Anti-coagulants

Anti-hypertensive drugs

202
Q

Statins

A

reduce the production of cholesterol, which is a component of atheroma. Build-up of atheroma can lead to blocked arteries

203
Q

Anti-coagulants

A

reduce the likelihood of blood clotting and therefore blocking an artery.

204
Q

Anti-hypertensive drugs

A

cause blood vessels to relax so their lumen diameter enlarges, reducing blood pressure.

205
Q

Surgical procedures

A

Stent - increase its lumen diameter so there is no restriction in the flow of blood to the cells it supplies.

Bypass -small section of blood vessel is removed from another part of the body. It is then used to re-route blood around a blockage in a coronary artery.

206
Q

Liver damage

A
207
Q

population

A

group of organisms of one species, living and interacting in the same area at the same time.

208
Q

community

A

all of the populations of different species interacting with each other in an ecosystem.

209
Q

ecosystem

A

unit containing the community of organisms and their environment, interacting together.

210
Q

Biotic factors

A

competition
disease
food supply
predation.

211
Q

As the number of prey increases…

A

so does the number of predators

212
Q

Why the time lag

A

because the predator needs to respond to changes in availability of food.

213
Q

Negatives of climate change

A

As water warms up, the solubility of oxygen in it decreases.

Most species of aquatic animals rely on oxygen for aerobic respiration.

214
Q

Growth of population phases

A
215
Q

Lag phase

A

population is very small and takes time to acclimatise to a new environment, become mature and start reproducing.

A doubling of small numbers does not have a big impact on the total population size, so the line of the graph only rises slowly with time.

216
Q

Log phase

A

no limiting factors.

Rapid breeding occurs in the population, resulting in significant increases in numbers. There are far more births than deaths.

217
Q

Stationary phase

A

Limiting factors such as shortage of food or a build-up of toxic materials in the environment start to have an effect, slowing down population growth.

It gets to the point where the number of deaths equals the number of births

218
Q

Death phase

A

number of deaths (mortality rate) becomes greater than the number of births so the population numbers start to decrease.

This may be due to lack of food, an accumulation of waste materials, disease spreading through the population, or an influx of predators

219
Q

Interdependence in ecosystems

A

predation, mutualism and parasitism

220
Q

Predator

A

carnivore which kills and eats other animals.

221
Q

Mutualism

A

close relationship between two organisms of different species where both organisms benefit.

222
Q

Parasitism

A

only one of the two organisms involved gains any benefit. The other is harmed.

223
Q

parasite

A

organism that lives on or in the body of another organism, the host

224
Q

How much light energy is harnesses by plants

A

1%

rest of light is reflected, or is used to evaporate water from leaves (transpiration), or warms up the soil, plants and air.

225
Q

At each successive stage in a food chain…

A

amount of biomass decreases

226
Q

Why amount of biomass decreases

A

organisms use some of the food they have obtained for energy to move, respire and maintain their body temperature.

some of the material is not digested or even eaten (plant roots in the case of the zebra).

227
Q

Tropic levels

A

producer → primary consumer → secondary consumer → tertiary consumer

228
Q

Draw carbon cycle

A
229
Q

Uses of glucose from photosynthesis

A
  • converted into starch storage
  • cellulose
  • fats + proteins
230
Q

Decomposes vs detritivores

A

Idk

231
Q
A
232
Q

Key features of wtaer cycle

A

Transpiration – plants release water vapour into the atmosphere, mainly through tiny pores called stomata in the leaves. The water evaporates inside the leaf before it is released.

Evaporation – occurs from the surface of bodies of water such as rivers, lakes and the sea.

Condensation – the water vapour in the atmosphere condenses to form clouds.

Precipitation – water in the clouds forms rain, snow, etc. which falls to the land and drains into water systems.

Osmosis – the process used by plant roots, bacteria and other organisms to take up water.

Excretion – from animals. Water is lost from animals in the form of sweat, exhaled air and urine. Faeces (a product of egestion not excretion) also contains some water.

233
Q

What’s the longest neuron

A

Sensory

234
Q

Shortest neuron

A

Relay

235
Q

Human bile

A

No lipase

236
Q

What does the gall bladder do

A

stores and releases bile

237
Q

Characteristics of bile

A

slightly alkaline so will have a low hydrogen ion concentration

238
Q

What does the stomach secrete

A

protease and stomach acid that has a high hydrogen ion concentration.

239
Q

What does 10% glucose conc mean

A

IT HAS WATER

240
Q

Where is amylase produced

A

Salivary glands and pancreas

241
Q

Where is lipase produced

A

Pancreas

242
Q

Where is protease produced

A

Mainly Pancreas and gastric glands in the stomach

243
Q

4 types of tissue

A

Muscle

Epithelial

Connective

Nervous

244
Q

Do RBC make up a tissue

A

YES - connective tissue

Blood is a type of connective tissue

245
Q

Do RBC have mitochondria

A

No

246
Q

What does the gall bladder do

A

Store and secrete bile - alkaline

247
Q

What does the pancreas secrete

A

Insulin / protease / lipase / amylase

248
Q

Where does insulin

A

Everywhere

249
Q

Where does glucagon act

A

Liver

250
Q

Universal donor

A

O

251
Q

Universal recipient

A

AB

BMAT (4 decks)

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