Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GCSEs > SB3, SB5 Biology (Paper 1) > Flashcards

SB3, SB5 Biology (Paper 1) Flashcards

1
Q

monomer definition

A

building block

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

asexual reproduction definition

A

reproduction that requires an organism to produce genetically identical offspring eg binary fission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Sexual reproduction definition

A

Reproduction that requires a male and female parent to produce genetically different offspring eg humans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Advantages of asexual reproduction

A

• Time and energy efficient
• Exploits different environments quickly
• Parents pass down desirable traits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

disadvantages of asexual reproduction

A

• No genetic variation
• Offspring are vulnerable to environmental changes (they’re unable to adapt)
• Diseases likely to affect whole population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Cells produced in sexual reproduction

A

4 haploid genetically different gametes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Advantages of sexual reproduction

A

• Genetic variation
• Has survival advantage as offspring can adapt to environment
• Less susceptible to disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Disadvantages of sexual reproduction

A

• Time consuming to find a mate and also to produce
• Difficult for those isolated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Diploid definition

A

Gamete containing the full set of chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

haploid definition

A

Gamete containing half the number of chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a nucleotide made up of?

A

• Phosphate
• Sugar
• Base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Polymer definition

A

a long chain of molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Genome definition

A

The entire set of the genetic material of an organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the complementary base pairs?

A

Adenine and Thymine, Cytosine
and Guanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are complementary base pairs held together by?

A

Weak hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how many bonds do thymine and adenine have compared to guanine and cytosine?

A

2 compared to 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

RNA meaning

A

ribonucleic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

examples of RNA molecules

A

mRNA and tRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Mutation definition

A

A rare and random change in the sequence of DNA bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Gene definition

A

section of DNA that codes for a particular sequence of amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what base do RNA molecules have instead of Thymine?

A

Uracil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 2 processes in protein synthesis

A

Transcription and Translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where does transcription take place?

A

in the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Where does translation take place?

A

In the cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the enzyme used in transcription?

A

RNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is RNA polymerase?

A

Enzyme that synthesises the mRNA strand by binding to the non coding section of DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what happens in transcription? (Takes place in nucleus)

A

• DNA’s double helix unzips (as weak hydrogen bonds break)
• Free mRNA nucleotides attach to complementary DNA bases
• mRNA strand is produced and it leaves the nucleus via nuclear pore (gap)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what takes place in translation? (Takes place in cytoplasm)

A

• mRNA attaches to ribosomes
• tRNA contains an amino acid binding site and also an anticodon to join to mRNA
• ribosome reads 2 codons at a time and every codon codes for one amino acid
• amino acids join through peptide bond
• polypeptide produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is a codon?

A

Triplet of bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What codes for an amino acid?

A

a codon (triplet of bases)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What does salt do in DNA extraction?

A

sticks the DNA together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Why is ethanol used in DNA extraction?

A

Ethanol precipitates the DNA (makes it a visible)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Why is detergent added in DNA extraction?

A

Breaks down nuclear and cell membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Why is the fruit mashed?
(DNA extraction practical)

A

To make the DNA easier to extract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Why is the ethanol ice cold?
(DNA extraction practical)

A

DNA is insoluble in cold ethanol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Why is the mixture filtered in DNA extraction?

A

to remove any debris (insoluble parts) from the mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What would the DNA appear as during extraction?

A

A stringy white precipitate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Precipitate definition

A

To be made visible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Allele definition

A

Variations of the same gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Phenotype definition

A

Observable characteristics that are expressed in an organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Genotype definition

A

Combination of alleles that controls a characteristic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Dominant allele

A

Allele that is always expressed even with only one copy present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Recessive allele

A

Allele only expressed when 2 copies are present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Homozygous definition

A

2 of the same alleles in a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Heterozygous definition

A

When 2 alleles in a gene are different

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Chromosome definition

A

Thread like structure of DNA that carry genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What did Gregor Mendel study?

A

How characteristics were passed down between pea plant generations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What does a punnet square diagrams show?

A

The possible combinations of alleles that could be produced in the offspring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Monohybrid inheritance

A

When a single gene controls the inheritance of characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Female sex chromosome

A

XX

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Male sex chromosome

A

XY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is a family pedigree diagram?

A

Used to trace the pattern of inheritance of a certain characteristic through family generations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What can we learn from a family pedigree diagram?

A

The probability that someone will inherit a disease or disorder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Codominance definition

A

When both alleles in a gene are expressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What blood group is recessive?

A

O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Sex linked inheritance definition

A

When alleles are found on the sex chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Why are there usually alleles on only the X chromosomes during sex linked inheritance?

A

X chromosomes are much larger than Y chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Polygenic meaning

A

Characteristics controlled by more than one gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Example of polygenic inheritance

A

Eye colour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Why are males more likely to have sex linked characteristics?

A

Males only have 1 X chromosome therefore the allele would always be expressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Structure of DNA

A

A double helix formed by two complementary strands of nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Magnification of eyepiece lens

A

X10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Monomer of starch

A

Glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Function of protease in DNA extraction

A

It breaks down proteins in cell and nuclear membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What are the types of mutation?

A

Insertions, deletions and substitutions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Insertion mutation definition

A

When a new base is randomly inserted into the DNA sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Deletion mutation definition

A

When a base in the DNA sequence is randomly deleted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Substitution mutation definition

A

When a base in the DNA sequence is randomly replaced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Causes of mutation

A

Gamma rays, x rays, ultraviolet rays, chemicals such as tar in tobacco

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What does a genetic variant affect in non coding DNA?

A

ability of RNA polymerase to bind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Effects of the inability of RNA polymerase to bind

A

less mRNA would be transcribed therefore less protein would be produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Cause of genetic variants in coding DNA

A

mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

Effect of the coding region of DNA being altered

A

The active site of an enzyme would change making it difficult for the substrate to bind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Why can mutations be advantageous to a species?

A

• New alleles are developed and this creates new phenotypes
• This can give an individual a survival advantage
(Eg being able to run faster)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What does a polypeptide do to form a protein?

A

It folds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Why is the solution heated up during the process of dna extraction?

A

To denature the enzymes and prevent the DNA from being digested

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

How is a gene represented in codominance?

A

I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

How is an allele represented in codominance?

A

A B or O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What are the blood groups?

A

A B AB O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

What are the 3 transport processes?

A

Osmosis, active transport and diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

What is the Human Genome Project?

A

A collaborative research effort to find out the human genome’s DNA sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

What does the Human Genome Project help with?

A

• Prediction and prevention of diseases
• Testing and treatment
• Development of new medicines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

How does the Human Genome Project help with prediction and prevention?

A

It helps doctors identify any faulty genes and give advice on diet to avoid/delay the disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

How does the Human Genome Project help with testing and treatment?

A

It allows doctors to identify faulty alleles quicker and provide treatment earlier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

How does the Human Genome Project help with development of medicines?

A

Doctors are able to design personalised medicines to improve effectiveness and reduce side effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

Disadvantages of the HGP

A

• someone may suffer from increased and unnecessary stress or anxiety • could be pressured into not having children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Variation

A

Differences between individuals of the same species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Continuous variation

A

when differences for a characteristic falls within a range

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

Discontinuous variation

A

When differences for a characteristic belongs in a group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

How is genetic variation caused?

A

Meiosis creates genetic variation between gametes produced by an individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

How is environmental variation caused?

A

Environmental factors eg climate, diet and culture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

What is discontinuous variation caused by?

A

genetic variation alone

93
Q

Examples of phenotypes caused by a combination of genetic and environmental variation

A

Height and Weight

94
Q

Examples of genetic variation

A

Blood group, eye colour, gender

95
Q

Examples of environmental variation

A

accent for a language, weight gain from eating too much, scar from an accident

96
Q

2 ways variation can be grouped

A

Continuous and discontinuous variation

97
Q

A combination of genetic and environmental causes contribute to

A

continuous variation

98
Q

(SB5)
Definition of health

A

A state of complete physical, mental and social wellbeing and not merely the absence of disease (WHO)

99
Q

What are the 3 types of well beings?

A

Physical, social and mental well being

100
Q

Disease definition

A

A problem with a structure or process in the body that hasn’t occurred from an injury

101
Q

What are communicable diseases caused by?

A

Pathogens entering the body changing how it works

102
Q

What are microorganisms that cause diseases called?

A

Pathogens

103
Q

Communicable disease meaning

A

A disease caused by pathogens which can be spread from person to person

104
Q

Non-communicable disease meaning

A

A disease not caused by a pathogen and is unable to be passed on from person to person

105
Q

Why can the presence of a disease lead to a higher susceptibility to other diseases?

A

• The immune system can be compromised
• Meaning that white blood cells are reduced making someone more vulnerable to infection

106
Q

What are the 4 pathogens?

A

• Fungi • Bacteria • Viruses • Protists

107
Q

Risk factors for obesity and malnutrition

A

A lack of exercise and a poor diet

108
Q

Cause and Effect of obesity

A

Eating significantly more calories than we burn • Increases the risk of other non communicable diseases (Type 2 diabetes and atherosclerosis)

109
Q

Cause and effect of malnutrition

A

Eating fewer calories than we burn (deficiency) • Causes brittle bones (low calcium levels)

110
Q

BMI is an abbreviation for

A

Body Mass Index

111
Q

Equation for BMI

A

Weight / Height²

112
Q

Risk factor for liver diseases

A

High intake of alcohol for a long period of time

113
Q

What are alcoholics more susceptible to?

A

Liver failure and cancer (uncontrollable cell division in DNA)

114
Q

Risk factor for lung diseases

A

• Smoking
• Tar produces carbon monoxide which reduces the lungs surface area
• This decreases gas exchange and the oxygen transported
• Leads to less respiration

115
Q

What diseases can smoking cause and why?

A

Pneumonia and lung cancer: • (Tar chemical causes lung cancer) • (Nicotine chemical causes atherosclerosis and high blood pressure)

116
Q

Define atherosclerosis

A

Build up of fat in arteries restricting the flow of blood

117
Q

Risk factors for cardiovascular disease

A

Smoking • Poor diet • Lack of exercise • High alcohol consumption

118
Q

Effects of atherosclerosis

A

• The individual will suffer from high blood pressure
• Increases chances of blood clots and heart attacks/strokes (CVD diseases)

119
Q

Definition of alveoli

A

Air sacks in the lungs with a large surface area to support gas exchange

120
Q

Carcinogens meaning

A

Chemicals that lead to mutation

121
Q

Risk factor meaning

A

Something an individual does to increase the likelihood of getting a disease

122
Q

What is cardiovascular disease?

A

• Disease of the heart / circulatory system
• Sometimes as a result of high cholesterol levels

123
Q

What does the immune system do?

A

Protects the body from infection

124
Q

Ways of measuring obesity

A

BMI and waist:hip ratio

125
Q

What chemical can cause atherosclerosis?

A

Nicotine

126
Q

How can pathogens spread?

A

• Air (pathogens in the air through the wind or from sneezing)
• Water (pathogens that live in dirty water)
• Oral transmission (pathogens ingested through food/water)
• Direct contact (exchange of saliva, blood or semen)
• Animal vectors (Animals that carry pathogens)

127
Q

What can the spread of pathogens lead to?

A

Diseases:

Airborne: Colds, influenza, Chalara ash dieback
Waterborne: Cholera
Oral transmission: Stomach ulcers
Direct contact: HIV, Chlamydia, Ebola
Animal vectors: Malaria

128
Q

How can infections such as colds or chalara ash dieback be prevented?

A

(airborne diseases)

Animals: Avoiding crowded areas, good hygiene, having ventilation
Plants: Preventing the import of trees or cutting down trees known to carry the disease

129
Q

How can infections such as cholera be prevented?

A

(waterborne diseases)

Avoiding poor quality water (eg by filtering or purifying tablets) and consuming clean water instead

130
Q

How can infections such as stomach ulcers be prevented?

A

(orally transmitted diseases)

Ensuring food is cooked properly and by having good hygiene standards

131
Q

How can infections such as Chlamydia and Ebola be prevented?

A

(Diseases through body fluids)

Wearing protection • screening after sex • Avoid sharing needles

132
Q

How can infections such as malaria be prevented?

A

(Diseases carried by vectors)

• Mosquito nets
• Taking malaria tablets
• Preventing the vector from reproducing (removing stagnant (dirty) water)

133
Q

Characteristics of bacteria

A

• Doesn’t always affect host cells
• Toxins it produces can damage cells
• It’s small and can reproduce very quickly

134
Q

What diseases can bacteria cause?

A

Tuberculosis • Cholera • Stomach ulcers • Chlamydia

135
Q

Tuberculosis and its effects

A

Bacteria is transmitted through the air • Caused by poor hygiene • Damages the lungs

136
Q

Cholera and its effects

A

• Waterborne disease spread through bacteria • Can lead to diarrhoea and vomiting

137
Q

Characteristics of protists

A

Diverse group of multi and unicellular organisms • Need a host to survive (parasite)

138
Q

Parasite meaning

A

Organisms that need a host to survive (Protists and Viruses)

139
Q

What disease can protists cause?

A

Malaria

140
Q

Malaria and its effects

A

• Disease spread by mosquitoes • Causes damage to the blood and liver

141
Q

Vector meaning

A

Carrier of a pathogen that causes a disease

142
Q

Fungi characteristics

A

• More common in plants than animals
• Can be single or multi cellular
• Produces spores and can infect organisms through the air

143
Q

Chalara Ash Dieback and it’s effects

A

• Airborne disease that affects ash trees • Causes dark patches, early leaf loss and bark lesions

144
Q

Characteristics of viruses

A

• Not considered a living organism • Do no carry out the 7 life processes • Takes over a host cell in order to reproduce (parasite)

145
Q

Ebola and its effects

A

• Virus transmitted through body fluids
• Causes headaches, rashes and haemorrhagic fever

146
Q

HIV (Human Immunodeficiency Virus) and its effects

A

• Sexually transmitted disease
• Destroys white blood cells in immune system
• Weakens the immune system leading to the onset of AIDS
• Therefore the body is unable to destroy the specific pathogen it may get infected by

147
Q

What disease can Fungi cause?

A

Chalara Ash Dieback

148
Q

What diseases can viruses cause?

A

Ebola and HIV

149
Q

Structure of viruses

A

• Have no cellular structure
• Have a protein coat (protects genetic material)
• Contain one type of nucleic acid (DNA or RNA)

150
Q

2 pathways viruses use to reproduce

A

• Lytic pathway • Lysogenic pathway

151
Q

Which pathway that viruses use is quickest?

A

The lytic pathway

152
Q

Describe the process of the lytic pathway

A

• Virus infects host cell and injects its DNA into cytoplasm (to control the cell’s machinery)
• Virus uses the enzymes in host cell to produce new virus particles
• Cell bursts (lyses) releasing virus particles into the host to infect more cells

153
Q

Describe the process of the lysogenic pathway

A

• Virus injects it’s DNA to the host cell and becomes incorporated into the host DNA
• As host cell replicates the viral DNA replicates
• No new viruses are made as the virus is dormant
• Changes in the environment causes the viral DNA to move to the lytic pathway to make new virus particles

154
Q

Why aren’t antibiotics effective on viruses?

A

• Viruses have a different structure to bacteria and they don’t carry out the same life processes
• They also reproduce inside host cells while bacteria don’t

155
Q

What type of defences do plants have to infections and infestations?

A

Chemical and physical defences

156
Q

Chemical defences plants have to prevent infection from pathogens

A

• They release chemical poisons (to deter/kill insects)
• Can release antibacterial chemicals to kill bacteria
[• Mechanisms to attract other insects (eg colour) in order to remove pests]

157
Q

Physical plants defences that help prevent infection

A

• Waxy cuticle acts as a barrier to microbes from entering
• Cellulose cell wall makes it difficult for pathogens to penetrate
• Thorns make it difficult for pests to access the plant tissue

158
Q

How would you test the soil in order to identify and detect plant diseases?

A

Take a sample of the soil and send it to a lab to test for pH or nutrient levels (to identify if it’s due to an environmental factor)

159
Q

How would you use drones to detect and identify plant diseases?

A

Use a drone to map out the distribution of symptoms to determine how the disease has spread (taking samples to test for pathogens)

160
Q

How would you use knowledge from books to identify and detect plant diseases?

A

Examine the area around the plant and use books to compare with known plant diseases to identify any pathogens or also a pattern

161
Q

Two examples of ways plant diseases can be identified

A

• DNA analysis (testing for pathogenic DNA)
• Monoclonal antibodies (identifying antigens from pathogens)

162
Q

What forms the first line of defense

A

Physical and chemical barriers

163
Q

Physical barriers in humans

A

• Skin (covers the body to prevent infection and forms a scab if it gets cut)
• Hairs and mucus in the nose (prevent pathogens from being inhaled)
• Mucus and cilia in lung airways (to trap pathogens and waft mucus to the back of throat)

164
Q

Chemical barriers in humans

A

• Stomach acid (contains hydrochloric acid strong enough to kill pathogens)
• Lysozymes (enzymes produced in tears from the eye that kill bacteria)
• Sebum (oily substance on skin that kills bacteria & fungi)

165
Q

What is the second line of defence?

A

The immune system

166
Q

What are the two main types of white blood cells?

A

Phagocytes (carry out phagocytosis) and Lymphocytes (produces antibodies)

167
Q

How do phagocytes protect the body from pathogens?

A

• Phagocytes have a sensitive cell membrane to detect pathogenic chemicals • They engulf and digest the pathogens (phagocytosis) after identifying them

168
Q

How do lymphocytes protect the body from pathogens?

A

• B-lymphocytes produce antibodies specific to the antigen on a pathogen to destroy it • Memory lymphocytes are produced to prepare for a secondary response

169
Q

What are vaccines?

A

When weaker or dead versions of a pathogen are injected into the bloodstream to trigger an immune response

170
Q

How does future infection affect immunity after vaccination?

A

Infection by the same pathogen will trigger a response much faster and larger than the initial (due to the memory lymphocytes in the bloodstream)

171
Q

Reasons why people may not be immunised against a disease

A

• Side effect concerns • Lack of access to healthcare • Immunodeficiency

172
Q

Herd immunity meaning

A

• When a large number of the population are vaccinated • This makes non - immunised people less likely to be infected

173
Q

What are antibodies?

A

Y shaped proteins with a shape complementary to an antigen

174
Q

What are antigens?

A

Molecules found on the surface of pathogens complementary to an antibody

175
Q

Function of goblet cells

A

They produce mucus to trap pathogens in lung airways

176
Q

2 types of medicines used to treat a disease

A

• Medicines that treat the cause (eg antibiotics) • Medicines that treat the symptoms (eg painkillers)

177
Q

What are antibiotics?

A

Medicines that help cure bacterial diseases by killing infective bacteria (eg penicillin)

178
Q

How do antibiotics work?

A

They inhibit processes in bacterial cells such as cell wall production or breaking down cell membranes (to prevent reproduction) • They only affect processes in bacteria so they aren’t harmful to host cells

179
Q

How can bacteria become resistant to antibiotics?

A

• People do not finish their course of antibiotics • Some bacteria have mutations which leads to variation therefore natural selection occurs (where the more resistant bacteria can survive)

180
Q

Evolution meaning

A

Gradual change in species over time

181
Q

What did Alexander Fleming discover?

A

He discovered penicillin through finding out that mould releases a chemical that kills bacteria

182
Q

What are new drugs tested for?

A

Toxicity (harmful side effects) • Efficacy (how well it works) • Dose (lowest dose that can make an impact)

183
Q

What is preclinical testing?

A

Drug testing done in a lab using cells, tissues and live animals • Efficacy and toxicity are tested

184
Q

What do clinical trials involve?

A

Drug testing on healthy volunteers at a low dose • Then tested on patients with the condition

185
Q

What do double blind studies involve?

A

Patients are split into a group getting the active drug and another group getting a placebo • Neither the doctor or patient knows what is being given • The lowest effective dose is tested once it’s found to be safe

186
Q

4 stages of drug development

A

• Preclinical testing • Clinical trials on healthy volunteers • Clinical trials on patients • Double blind study

187
Q

Disadvantages of using other mammals for drug testing

A

• It could cause harm
• Could affect them differently from humans

188
Q

Placebo meaning

A

An inactive substance given to someone instead of a medicine

189
Q

Aseptic technique meaning

A

Method that prevents contamination by harmful microorganisms

190
Q

Aseptic technique examples

A

• Not putting sterile equipment down (eg pipette - to prevent microorganisms being transferred)

• Strongly heating the neck of the bottle of bacteria culture (to kill any microorganisms and cause air to move away)

• Lifting the Petri dish lid slightly (to reduce the micro organisms contaminating the agar)

• Placing the pipette in disinfectant (kills any bacteria on it)

191
Q

Why do we mark the bottoms of the Petri dish into different sections?

A

It helps us know which antibiotic disc went where

192
Q

Why is a control disc placed in the Petri dish?

A

To ensure that the bacteria has grown and that any clear space is due to the antibiotics

193
Q

Why is the lid taped onto the Petri dish at the end?

A

To seal the dish and reduce anaerobic pathogens growing

194
Q

Why is the Petri dish turned upside down?

A

To prevent condensation onto the agar

195
Q

What variable goes on the x axis?

A

Independent variable

196
Q

What variable goes on the y axis?

A

Dependent variable

197
Q

How is the bacteria culture spread onto the agar plate and why?

A

Using the forceps with a side to side motion as it ensures all the agar plate is evenly covered

198
Q

Examples of CVD

A

• Coronary heart disease (disrupted blood flow to heart)
• Strokes (disruption of blood flow to brain)
• Aortic disease (type of blood vessel affected)

199
Q

How does cholesterol increase the risk of CVD?

A

• It contributes to the build up of fatty plaques inside the coronary arteries
• This reduces the flow of blood therefore less oxygen is supplied

200
Q

How do you calculate zone of inhibition?

A

πr²

201
Q

Ways of treating CVD

A

• Surgical procedures
• Lifelong medication
• Lifestyle changes

202
Q

What surgical procedures can treat CVD?

A

• Coronary bypass surgery
• Heart transplants
• Stents

203
Q

How does coronary bypass surgery (surgical procedure) treat CVD?

A

• It involves replacing damaged vessels with healthy vessels from elsewhere in the body • This allows blocked sections of the heart to be bypassed/replaced • Supports uninterrupted blood flow

204
Q

How do heart transplants (surgical procedure) treat CVD?

A

• It involves replacing a failing heart with a healthy heart from a dead donor • It carries the risk of rejection and therefore the heart may not work at all • Patients would need to be on medication permanently

205
Q

How do stents (surgical procedure) treat CVD?

A

• A narrow tube is inserted into the blocked vessel so that the lumen widens • This increases the blood flow and therefore more oxygen is delivered • Balloon and tube are then removed

206
Q

What is lumen?

A

The space inside a blood vessel

207
Q

How does lifelong medication treat CVD?

A

• It involves the use of statins
(drugs used to reduce levels of cholesterol)
• They block an enzyme in the liver needed to make cholesterol
• This slows down the rate of fatty material building up in the blood

208
Q

What drug reduces the levels of cholesterol in the blood?

A

Statin

209
Q

How do lifestyle changes treat CVD?

A

• Smoking prevention reduces likelihood of atherosclerosis

• Maintaining a balanced diet eg:
- Low cholesterol (reduces atherosclerosis likelihood)
- Low salt (reduces high blood pressure risk)

• Exercising to maintain a healthy weight

210
Q

What are monoclonal antibodies?

A

Identical copies of one type of antibody

211
Q

Where is cholesterol synthesised?

A

In the liver

212
Q

How are monoclonal antibodies formed?

A

• Isolate antigen from the pathogen

• Inject the antigens into a mouse to stimulate an immune response

• Lymphocytes will produce antibodies complementary to the antigen

• The lymphocytes are then removed from the mouse and fused with fast-dividing myeloma (tumour) cells

• This produces hybridoma cells that divide rapidly to produce millions of monoclonal antibodies specific to the original antigen

213
Q

Scientific uses of monoclonal antibodies

A

• Pregnancy tests
• Cancer diagnosis (locate blood clots)
• Cancer treatment

214
Q

How are monoclonal antibodies used in pregnancy testing?

A

• The pregnancy test detects a hormone (hCG) in urine
• The hormone binds to the antibody on the test as they’re complementary
• Antibody has a coloured bead attached to it
• A line appears because they’re immobile antibodies in the test window

215
Q

Advantages of using monoclonal antibodies

A

• They only bind to molecules on a specific cell therefore no healthy cells are affected
• This causes fewer side effects

216
Q

How are monoclonal antibodies used to treat diseases eg cancer?

A

• The monoclonal antibody is bound to a radioactive substance / drug
• It delivers the substance to the cancer cell and stops it from growing and dividing
• Other cells in the body are left unharmed

217
Q

How are monoclonal antibodies used to locate blood clots?

A

• Radioactively labelled monoclonal antibodies bind to proteins in a blood clot
• A special camera creates an image of the radiation
• This locates the blood clot

218
Q

Ways of visually detecting a plant disease

A

• Stunted growth
• Spots on leaves
• Discolouration

219
Q

Reagent for protein

A

• Biuret solution (tests for peptide bonds)
• Changes from blue to purple in the presence of proteins

220
Q

Reagent for reducing sugars

A

• Benedict’s solution
• Colour changes from blue to green/yellow (in low sugar amounts) or red (in high sugar amounts)

221
Q

Describe the emultion test

A

• Add ethanol to food
• Mix them together
• If a white precipitate is formed, lipids are present

222
Q

How many types of nucleotides are there?

A

4 (as there’s 4 bases)

223
Q

Equipment used to measure rate of transcription

A

Potometer

224
Q

What colour does hydrocarbon indicator turn during the lack of co2?

A

Turns from red to purple

225
Q

Genetic variation meaning

A

Differences in the inherited genes of an individual due to variation from sexual reproduction

226
Q

Environmental variation meaning

A

Differences in the conditions an organism develops in

227
Q

Differences between light and electron microscopes

A

Light microscopes:
• Relatively cheap and easy to use
• Rely on light to magnify images
• Resolution limited to 0.2 um (micrometers)

Electron microscopes:
• Very expensive and hard to use
• Use electrons rather than light
• Max resolution 2000x better
• Can be used to study sub cellular structures

228
Q

What is an um?

A

A micrometer

229
Q

How many ums are in a mm?

A

1000

GCSEs (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions