Brainscape's Knowledge GenomeTM

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


See full index

Biology Exam Questions > Topic 3/4 > Flashcards

Topic 3/4 Flashcards

1
Q

Two differences between tissues and organs (2)

A
  • Tissues made of cells, organs made of tissue
  • tissue made of similar types of cells, organs made of different tissue
  • Organs have more functions than tissuea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is meant by the term polygenic inheritance? (2)

A
  • Characteristics that show continuous variation are controlled by genes at many loci.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Significance of anaphase (1)

A
  • Produce genetically different daughter cells from parent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe end result of mitosis in cell cycle (2)

A
  • Chromatids separated

- Nucleus divided

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

Describe end result of S phase in cell cycle (2)

A
  • DNA replicated

- Quantity of DNA doubled

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

Explain what is meant by the term sustainable (2)

A
  • Resource that can be renewed/not run out

- Available to future generations

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

How has use of the Hardy Weinberg equation helped determine if evolution has taken place? (2)

A
  • Identify changes in allele frequency over time

- If frequency has changed, evolution has taken place

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

How are breeding programs in zoos designed to reduce risk of inbreeding? (4)

A
  • Selection of genetically different mates
  • Use of mating records/stud books
  • Exchange of animals between zoos
  • Exchange of gametes between zoos
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In reference to natural selection how might animals become extinct? (3)

A
  • Predation/disease
  • Change in environmental conditions
  • Inability to reproduce
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define biodiversity (2)

A
  • Genetic diversity within a range of species
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Define niche (2)

A
  • The way in which an organism interacts/exploits its habitat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Suggest how inbreeding can lead to genetic defects (2)

A
  • Small gene pool as closely related animals mate
  • Results in interbreeding depression, more homozygous genotypes
  • Increased homozygous recessive genotypes for genetic defects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Use of Hardy Weinberg’s equation is only valid when what occurs? (1)

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

describe process of cell specialisation (4)

A
  • Stimulus causes genes to become active
  • Active genes are transcribed
  • mRNA translated to produce proteins, change is permanent
  • Proteins modify the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are pluripotent stem cells? (3)

A
  • Unspecialised cells that can differentiate to give rise to almost any cell in the body, except totipotent cells
  • Some genes in pluripotent stem cells are inactivated meaning they can’t differentiate into all cell types.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain how organisms can be classified into taxonomic groups (2)

A
  • Organisms with similar characteristics placed into same group
  • Details of classification eg similarities in DNA, monocellular phylogeny and behavioural similarities.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How can independent assortment give rise to genetically varied gametes? (2)

A
  • Random arrangement of chromosomes

- Chromosomes from homologous paris

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

How can organelle be identified as Golgi apparatus (3)

A
  • Curved membrane bound sac
  • Different size sacs
  • Smooth surface, no ribosomes attached
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe how society controls use of embryonic stem cells in medical research (4)

A
  • Regulatory bodies like the high court set ethical aspects
  • They judge what is acceptable based on codes of conduct
  • Check source of stem cells is acceptable
  • Enforce concept of human cloning being illegal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe and explain how the acrosome reaction prevents more than one sperm fertilising an egg (4)

A
  • Sperm cell uses lysosomes to enter zona pellucid and fertilise egg cell
  • Vesicles fuse with egg cell
  • Cortical reaction is triggered, vesicles use exocytosis to release cortical granules
  • Zona pellucida thickens
    Cell membrane thickens and releases chemicals deterring sperm cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Advantage of selecting various sizes of seeds for long-term storage (3)

A
  • Maintain genetic diversity
  • More chance of having beneficial alleles
  • Increased chance of future survival if environment changes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe what seedbanks do to seeds to ensure long-term conservation of species (3)

A
  • Assess seed viability, selecting seeds with living embryo
  • Sterilisation of seed surface
  • Drying seed and storing it at low temperatures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Explain how meiosis gives rise to genetic variation in gametes (2)

A
  • Independent assortment gives rise to new combinations of paternal and maternal chromosomes
  • Swapping over involves swapping over of chromosomes at centromeres
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why are placebos used to test efficiency of new drugs (2)

A
  • Inactive or no drug is used as a control

- Psychological effects of taking the drug or placebo can be assessed

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

Describe the events of the anaphase stage in mitosis (2)

A
  • Chromatids split

- Moved to opposite side of cell by spindle fibres shortening

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

How does crossing-over give rise to different combinations of alleles in gametes (2)

A
  • Exchange of alleles between non-sister chromatids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Describe + explain features and functions of sperm cells (4)

A
  • Many mitochondria provide ATP for swimming

- Flagellum - helps cell move towards ovum

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

Describe differences between species richness and genetic diversity (2)

A
  • Species richness is number of species within a habitat

- Genetic diversity is number of alleles in one species

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

What is meant by molecular phylogeny (3)

A
  • Molecular differences in DNA in proteins

- They are the evolutionary relationships between organisms

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

What is meant by gene locus (2)

A
  • Location of gene on chromosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How could species richness be measured (1)

A
  • Count the number of species in the area of interest
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Why use double-blind trials (1)

A
  • To remove bias
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is an endemic species (1)

A
  • Species found only in one specific geographical location
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What structure is not present when cell undergoes mitosis (1)

A
  • Nucleolus
35
Q

Describe and explain 3 ways in which human sperm cell is specialised for its function (6)

A
  • Streamlined shape reduces resistance when swimming
  • Acrosome contains enzymes to digest the zona pellucida
  • Haploid nucleus allows restoration of 46 chromosomes at fertilisation
  • Large number of mitochondria provide energy for movement
  • Flagellum allows cell to swim to ovum
  • Receptors on cell surface membrane bind to egg cell membrane
36
Q

What is meant by the term haploid nucleus? (2)

A
  • Half the number of chromosomes found in a somatic cell
  • One chromosome from each homologous pair
  • Type of nucleus found in gametes
37
Q

Suggest how captive breeding programs in zoos ensure genetic diversity is maintained in species (5)

A
  • Captive breeding increases population size
  • Stud books kept of breeding programs
  • Zoos select mates
  • Inter-exchange of animals between zoos for breeding, reduces risk of interbreeding
  • Genetic diversity can be measured using DNA profiling
38
Q

Describe what occurs during prophase (4)

A
  • Chromatin condensed, chromosome becomes visible
  • Nuclear membrane breaks down
  • Nucleolus disappears
  • Centrioles move to opposite poles and spindle fibres form
39
Q

Suggest 3 factors that could affect survival chances of ferrets when reintroduced to their habitat (3)

A
  • Availability of food or prey
  • Intraspecific competition between other ferrets for resource
  • Interspecific competition between other species for resource
40
Q

What is meant by the term mitosis? (3)

A
  • Involves prophase, metaphase, anaphase and telophase

- Produces two genetically identical nuclei to the original

41
Q

Describe structure of cell wall in xylem vessel (4)

A
  • Microfibrils consisting of cellulose held together by hydrogen bonds
  • Lignin in cell walls for support and strength, could be spiralled or in a criss-cross pattern
  • Bordered pits
  • Pectin and hemicellulose also present in walls
42
Q

Explain function of mitochondria in sperm cell (2)

A
  • Site of aerobic respiration

- Provides energy in the form of ATP for movement

43
Q

what is mean by the term ecological niche (1)

A
  • organisms’ roles in the ecosystem
44
Q

explain function of acrosome in sperm cell (2)

A
  • Contains enzyme

- Digestion of zona pellucida

45
Q

Describe the role of the Golgi apparatus (4)

A
  • modifies proteins, eg addition of carbohydrate chains
  • packages proteins in vesicles for transport out of the cell by exocytosis
  • Name of vesicle pinched off Golgi is a lysosome
46
Q

Smooth ER present in? (1)

A
  • animal and plant cell only
47
Q

Differences between pluripotent and totipotent stem cells (2)

A
  • totipotent cells give rise to any type of cell
  • pluripotent can’t give rise to all cells in body
  • only totipotent cells can give rise to other totipotent cells
  • Pluripotent can’t give rise to entire human being, totipotent can
48
Q

Suggest how scientific ideas are critically evaluated (3)

A
  • Scientists findings published in journa;s
  • idea presented as scientific conferences and are peer reviewed
  • other scientists report experiments to check validity and reliability
49
Q

describe how you would use plant tissue culture to show totipotency in plant seedlings (4)

A
  • Take seed cuttings
  • Use agar medium with growth substances and regulatory hormones
  • Use aseptic techniques when handling the culture, cover lid to prevent contamination
  • Look too see if roots/leaves form
50
Q

what is meant by double blind trial (2)

A
  • One set of patients given drug, the other a placebo
  • neither patient nor doctor knows if treatment contains drug or not
  • removes bias from the results
51
Q

Two events that take place during interphase (2)

A
  • Synthesis of organelles

- Replication of DNA

52
Q

name process that must occur in genetic material before chromosomes become visible (2)

A
  • DNA replication

- DNA doubled

53
Q

why are stem cells from bone marrow of patient able to repair damage to heart tissue of patient? (5)

A
  • Stem cells are from the same person, no rejection
  • stem cells receive stimulus from surrounding heart cells
  • This causes certain genes to be activated, mRNA transcribed off active genes
  • mRNA translated into protein on ribosome
  • these proteins ensure the cell develops into heart cells
54
Q

suggest why stem cells can be used to reverse paralysis from a spinal injury (2)

A
  • Stem cells are totipotent and can give rise to specialised cells
  • these can replace damaged cells
  • the cells are capable of continuous division
55
Q

3 structural differences between prokaryotic/eukaryotic cells (3)

A
  • Eukaryotes have membrane bound organelles
  • prokaryotes have plasmids, eukaryotes do not
  • DNA in nucleus of eukaryotes
  • DNA is linear in eukaryotes, circular in prokaryotes
56
Q

describe how contamination of tissue culture is avoided (2)

A
  • Aseptic techniques like heating the agar to kill off micro-organisms
  • Used sterilised containers and equipment
  • Seal container to prevent contamination
57
Q

Explain why contamination of tissue culture is avoided (2)

A
  • contaminants can cause infection to the plant culture
  • contaminants compete for nutrients
  • they can cause poor growth, decay or death
58
Q

Why are drugs tested on animals and healthy humans (2)

A
  • testing on animals for toxicity
  • testing on healthy humans to determine side effects
  • testing on humans to analyse how drug is metabolised
59
Q

Describe structure of cellulose in cell wall (3)

A
  • cellulose is a polymer of b-glucose
  • cellulose held together by hydrogen bonds
  • arrangement of microfibrils in criss-cross
  • Presence of pectin
60
Q

describe how structure of xylem vessels allow transport of water (2)

A
  • Hallow and vessels are open at both ends
  • vessels have pits and are strong so they don’t collapse
  • Lignin provides waterproofing and strength to cell walls
61
Q

Suggest how natural selection leads to evolution (5)

A
  • Genetic variation within population
  • selection pressure changes for example new frui on taller trees
  • Animals with beneficial advantage of longer necks and legs are able to reach fruit on taller trees
  • Organism with beneficial characteristic more likely to survive till adulthood and reproduce
  • pass on advantaged genes to offspring
  • Over time allele frequency changes and the population becomes isolated, could be geographically.
62
Q

explain why bone marrow cells are source of stem cells (2)

A
  • bone marrow contains unspecialised cells

- these are needed as they need to have the ability to differentiate into heart cells

63
Q

Define tissue (2)

A
  • group of cells

- Cells work together to achieve one function

64
Q

how does lignin add strength to xylem tissue? (2)

A
  • Lignin holds microfibrils together

- Lignin keeps microfibrils parallel

65
Q

explain how calcium, nitrate and magnesium ions are used by plants (3)

A
  • nitrates for production of amino acids
  • Calcium for pectin
  • magnesium for chlorophyll
66
Q

Named process observed when undergoing meiosis not mitosis (2)

A
  • Crossing-over

- chiasmata

67
Q

Explain importance of nitrate ions in growth of plants (2)

A
  • Amino acids
  • Used in synthesis of DNA
  • Amino acids used for synthesis of proteins
68
Q

why are stem cells taken from patient and not anyone else (2)

A
  • Cells are genetically identical

- No rejection

69
Q

Devise an investigation to determine the effects of exposure time to agil on the rate of mitosis in onion root tips (6)

A
  • use a controlled conc of agil eg 2moldm^-3
  • Use the same age of onions
  • Expose the roots for different time intervals eg 4, 8, 12, 16 hours
  • prepare your root tip, cut tips and place them in hydrochloric acid for 5 minutes
  • after rinsed place on microscope slide with a drop of toluidine blue stain
  • count number of cells undergoing mitosis to calculate the miotic index
70
Q

Describe how nitrate ions are transported from the roots to the leaves (2)

A
  • Through Xylem vessel

- In water

71
Q

Explain the effects of shortages in magnesium ions in plants (3)

A
  • Limited chrolophyll production
  • Lack of glucose due to less photosynthesis
  • Plant leaves may be yellow
72
Q

Explain why some bacteria can grow rapidly in skin wounds (3)

A
  • Warm temp increase rate of reactions in bacteria
  • Energy source from blood
  • Water available for bacteria to function
73
Q

Explain why starch must be broken down before being used by cells in growing plants (1)

A
  • To produce glucose

- Used for respiration

74
Q

Justify the continued functioning of SGSV (3)

A
  • Conserves genetic diversity of crops
  • Crops are protected from disease
  • Help ensure future food security
75
Q

Describe how each gamete recieves only one allele from each gene (2)

A
  • In meiosis homologous chromosomes are separated from each other
  • Chromatids are separated from each other
76
Q

Describe two ways in which the structure of starch is related to its function (4)

A
  • Made up of many glucose molecules
  • Provides energy storage
  • Large molecule so is unreactive
  • compact so more can be stored
  • branches allow rapid mobilisation
77
Q

Name the part of a chromosome occupied by a gene (1)

A

locus

78
Q

Explain how a group of cells can produce the same enzyme (3)

A
  • Genes can be activated/deactivated
  • Cells receive the same stimuli
  • All cells have the same gene for enzyme activated
79
Q

Even though offspring are from the same parents, explain why the offspring may be genetically different (2)

A
  • Zygote formed from different gametes
  • Each gametes contains different combination of alleles
  • Due to independent assortment
80
Q

explain why a second sperm cannot fertilise an egg cell (3)

A
  • Cortical reaction
  • Resulting in thickening of zona pellucida
  • Other sperm cannot reach cell surface membrane
81
Q

Compare and contrast clinical drug trials and William Withering’s soup trails (3)

A
  • Both used different doses to deduce safe dose
  • William did not use healthy volunteers, drug trails do
  • William did not use placebo, drug trails do
82
Q

Explain how the primary structure of collagen determines its properties (4)

A
  • insoluble due to many hydrophobic R groups
  • strong due to triplet helix
  • many repeating amino acid sequences
  • many small R groups so triple helix can form
83
Q

explain how freezing sperm could affect the success of captive breeding programs (4)

A
  • Sperm from different males frozen to increase genetic diversity
  • frozen sperm always available if species numbers are too low
  • freezing could result in poor viability, less successful fertilisations
  • more sperm used if viability is low, reducing stocks
84
Q

compare and contrast the structures of starch and glycogen (4)

A
  • both polysaccharides
  • both joined by glycosidic bonds
  • starch consists of two polysaccharides, glycogen only 1
  • starch has 1.4 and 1.6 glycosidic bonds, glycogen only has 1,6

Biology Exam Questions (4 decks)

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