WACE shit Flashcards
1
Q
Approximately when did life first evolve on Earth?
A
approximately 3.5 billion years ago
2
Q
List three structural properties of an RNA molecule.
A
type of nucleic acid
1–3
contains ribose sugar
phosphate group
made up of nucleotides/nitrogenous bases/contains C, G, A
and U bases
single stranded molecule
3
Q
Define the term ‘genetic code’.
A
set of rules that determine how genetic information/nucleotide
sequences/codons in DNA/RNA is translated into amino
acids/determines amino acids in a protein
how information in DNA/RNA is converted into a protein
base triplet code that determines amino acids in a protein
4
Q
Outline how the fact that all living organisms use essentially the same genetic
code provides evidence for evolution.
A
Organisms inherit genetic code from their ancestors.
All organisms can be traced back to a single ancestor.
5
Q
role of RNA polymerase: in protein synthesis
A
(enzyme that) catalyses the synthesis of mRNA from DNA
or adds nucleotides to mRNA molecule
6
Q
role of transcription in protein synthesis
A
process of making a mRNA copy of a DNA/gene sequence 1
7
Q
role of anticodon in protein synthesis
A
(three) nucleotides in tRNA that is complementary to codon in mRNA
or (three) nucleotides in tRNA that bind to mRNA
or that determine which amino acid tRNA carries
8
Q
role of ribosome in protein synthesis
A
reads the mRNA/site of protein synthesis/performs translation/links amino
acids (in correct order)
9
Q
role of amino acid in protein synthesis
A
amino acids are the building blocks of protein/polypeptide
or sequence of amino acids determine type of protein
10
Q
Define the term ‘mutation’
A
A permanent change in DNA/a gene/a chromosome. 1
11
Q
List three distinctly different causes of mutation
A
errors in DNA replication
errors in cell division
mutagens/environmental factors
12
Q
Explain the role that mutation has played in diversifying life on Earth.
A
mutation is source of genetic variation or of all new alleles/new genes
these are the basis of differences among organisms
mutations have accumulated over time
differences among organisms/the diversity of organisms have increased over time
without mutation all organisms would be the same (except for environmental differences)
13
Q
Outline two main ways in which rodents that live in deserts lose water to the
environment.
A
breathing/exhaling/panting and
evaporation of moisture from lungs
excretion/urination/expelling waste/defaecation and
water is needed to excrete urea/urine or to expel faeces/waste
sweat glands/sweating and
evaporation of water from skin
14
Q
Kidney mass as a percentage of body mass is often higher in rodents that live in deserts
than in related species that live in moist environments. Explain why.
A
desert rodents need to minimise water loss or rodents in moist
environments do not need to minimise water loss
the kidney is used to maintain salt-water balance/control the amount of
water excreted/reabsorb water
(in desert rodents) large amounts of water are reabsorbed/recovered
from urine or urine is highly concentrated
larger kidney size gives larger area for water reabsorption or the Loop
of Henle is longer in (some) desert rodents
the Loop of Henle (is the part of the kidney that) recovers the water
15
Q
Define the term ‘gene pool’.
A
all of the genetic information/genes/alleles in a population/species
16
Q
Define the term ‘allele’.
A
a form/version of a gene
17
Q
Propose an explanation for the increase in the frequency of the AceR allele in
Population 2 during the study.
A
Natural selection/selective pressure of insecticide
the AceR allele gives resistance to the insecticide
individuals with AceR allele survive/reproduce/are fitter/produce more
offspring
the AceR allele is passed to offspring/inherited
more individuals in the next generation have AceR allele
process is repeated over multiple/10 generations leading to
progressive increase in frequency of the AceR allele
18
Q
Distinguish between a dominant and a recessive allele.
A
dominant – only one copy of allele is needed for an individual to show phenotype or heterozygote will show phenotype
recessive – two copies of allele are needed for an individual to show phenotype or only recessive homozygote will show phenotype or can be masked by a dominant allele
19
Q
Distinguish between autosomal and sex-linked alleles
A
autosomal – alleles are on autosomal chromosomes or alleles are not on sex chromosomes or two alleles are present in both males and females
sex linked – alleles are on sex chromosomes or X/Y chromosome or two alleles are present in females and only one is present in males
20
Q
Outline an approach that can be used to
determine whether an unaffected individual has the SLS allele
A
- DNA sequencing or (comparative) genomics 1
- determine nucleotide sequence
- compare genomes/DNA sequences of affected and unaffected sheep
- take samples from affected and unaffected sheep
- extract DNA
- use PCR/restriction enzymes/gel electrophoresis
21
Q
Explain what a polygenic trait is.
A
- controlled/influenced by the alleles at many genes/by many genes
- also influenced by the environment
- trait shows many different phenotypes in a population or trait shows continuous variation/a normal distribution in a population
22
Q
Outline one advantage and one disadvantage of producing this line of sheep by artificial selection
rather than transgenesis.
A
ADVANTAGE
- (breeding sheep is a) natural process
- can be done on farm/does not require specialist equipment/less controversial
DISADVANTAGE
- artificial selection changes allele/gene frequencies gradually
- slower process or will take many generations to produce desired line
23
Q
Define ‘homeostasis’
A
The process organisms use to maintain constant internal
conditions or ability to maintain stable internal conditions/state.
24
Q
State the aspect of homeostasis in the frog host that is disrupted by
chytridiomycosis.
A
salt-water balance/water balance/salt balance/osmosis/
gas exchange
25
how chytridiomycosis is transmitted between frogs.
pathogen/fungi/zoosporangia release spores/zoospores (into
environment/water)
spores/zoospores are motile/swim/transported by water to new frog
by direct/skin contact between frogs
(spore/zoospores) invade skin/epidermal cells of new frog.
26
Distinguish between the reliability and validity of an experiment.
Reliability is the chances of getting the same/similar result (if the experiment was to be repeated)
Validity is when the experiment tests the hypothesis/what is intended to be tested.
27
Explain how knowledge of the reproductive behaviour of a frog species can assist with
conservation planning to minimise population decline.
- reproductive behaviour influences reproductive success
- can use information to predict/understand how it will change
- population size/population dynamics
- document courtship/mating behaviour
- can add protections to minimise disruptions to behaviour
- can manipulate behaviour/population sex ratios
- can ensure species can behave normally in captive breeding
- document nesting sites
- can protect nesting sites/add suitable/artificial nesting sites
28
Explain the circumstances in which it is an advantage to an animal to excrete uric acid.
dry/low water conditions
(uric acid) is not very soluble
requires very little water to excrete
compensates for high cost of production (in dry environment)
in eggs where it is not possible to remove waste
(uric acid) has low toxicity
minimises weight for flight
29
On the basis of the above information, how many chromosomes would be present in a
diploid cell of a mule? Explain your answer.
horse sperm/egg/gamete/haploid cell = 32 chromosomes
donkey sperm/egg/gamete/haploid cell = 31 chromosomes
egg and sperm/gametes fuse/haploid cells fuse to form
zygote/mule/offspring
32 + 31 = 63
30
Explain why mules cannot produce functional gametes.
meiosis is used to produce gametes
meiosis is disrupted
mules have an odd number of chromosomes/chromosomes do not
match up/chromosomes do not form pairs (in meiosis)
(therefore) chromosomes do not segregate (to different
poles/gametes) correctly
produce gametes with the wrong number of chromosomes/genes
mules do not have all of the genes/chromosomes needed (to
produce functional gametes)
mules are hybrids/sterile or mules have the genes/chromosomes of
two different species
31
Explain how biologists know about the evolution of the forefeet in horses over the past
50 million years.
fossils/fossil record
preserved bones (from forefeet)
bones are likely to be preserved/common in the fossil record
compare fossil evidence with forefoot in modern horse/comparative
anatomy
can age fossils using index fossils/date bones/date rock (in which the
fossil was found)
32
Is the evolution of horse forefeet an example of microevolution or macroevolution?
yes lol
evolution above the level of the species
major or large-scale changes
over a long period of time/millions of years
trend within a large group/taxon
accumulation of many small/microevolutionary changes
33
A non-albino male and a non-albino female guinea pig were crossed and produced a
litter containing some albino and some non-albino offspring. Explain in words how nonalbino guinea pigs can produce albino offspring.
albinism is recessive/coloured fur is dominant
need two recessive alleles/need to be homozygous to be albino
male and female parents were (both) heterozygotes/carried albino
allele
thus possible to get one albino allele from each parent
34
Both male and female albino offspring were produced in the cross described in part (a).
On this basis, explain in words why albinism cannot be a sex-linked trait in guinea pigs.
X-linkage
not possible for non-albino parents /non-albino father to produce
albino daughter/female offspring
father/males only has one X chromosome
father does not have albino allele on X chromosome (otherwise it
would be albino)
daughters/female offspring inherit one X chromosome from father
therefore not possible for any daughter/female offspring to have two
albino alleles
Y-linkage
male parent is not albino therefore no albino allele on Y chromosome
albino sons/male offspring only possible if male is albino OR albino
sons/male offspring not possible if male parent is not albino
albino daughters/female offspring are not possible because they do
not have Y chromosome
35
Albino guinea pigs are common in captive populations but rare in wild populations.
Explain this difference.
albino favoured in captivity/selectively breed/breed by
humans/artificial selection
(albinos) pass albino allele to offspring
albino allele increases in frequency
coloured favoured in wild or albino not favoured
by natural selection
coloured better camouflaged/tolerant of sunlight or albino poor
camouflage/sensitive to sunlight
coloured breed more or albino breed less
pass coloured allele to offspring or albinos do not pass allele
coloured allele frequency increase or albino allele frequency
decreases/kept low
36
Explain how biotechnology can be used to determine the father of the litter.
DNA profiling
extract DNA
Polymerase chain reaction (PCR)/amplify gene or alleles or markers
screen samples using gel electrophoresis or sequence samples
specific details of any of the methods (e.g. gel electrophoresis DNA
samples separate according to size)
compare profile of all guinea pigs
offspring will have alleles/markers from male (and female) parent
37
Malaria is caused by a protist. Describe the main structural features of protists.
eukaryote/eukaryotic cell
nucleus
(may have) multiple nuclei
mitochondria/membrane bound organelles
(usually) single cell
(usually) small/microscopic
cilia/flagella/pseudopodia
may have cell wall or protective outer layer
38
Describe how malaria is transmitted from an infected person to an uninfected person
female mosquito/Anopheles mosquito
vector
bites/takes blood from infected person
blood contains protist
protist reproduces in mosquito
transmitted when mosquito bites
transmitted in (mosquito) saliva
39
Outline two distinctly different methods of controlling the spread of malaria.
use of insecticides
to kill mosquitoes
or
eliminate standing water/oil on water
remove/disrupt mosquito breeding
or
modify human behaviour/avoid being outdoors at times when
mosquitoes are active/use netting/use repellent/wearing protective
clothes
avoid being bitten (stops transmission)
or
biological control of mosquito
specific details of biological control (e.g. mosquito fish)
or
anti-malaria drugs
fewer infected people/fewer pathogens in the people
40
Describe the distribution of malaria.
rarely occurs above or below the tropic of cancer or the tropic of
capricorn respectively
centered on the equator/occurs mainly between the tropic of cancer
and the tropic of capricorn
most countries either have malaria transmission or not
very few areas are at limited risk of malaria transmission
refers to any specific country or area where malaria transmission
does occur
states any environmental or economic factor regarding temperature
and rainfall and malaria transmission
41
Explain why tuberculosis is
much more widely distributed than malaria.
different types of transmission
tuberculosis is caused by bacteria
transmitted from person to person/no vector involved
(tuberculosis) transmitted by close contact/droplets/sneezing
therefore (potentially) spreads (readily) to wherever there are people
modern transport/movements of people helps spread/tuberculosis
asymptomatic
malaria is transmitted through vector/mosquitoes/transmitted
indirectly
distribution of vector influences distribution of disease or distribution
of malaria reflects distribution of (Anopheles) mosquito that transmits
it/vector
42
explain the process of binary fission
Chromosome/Genetic material is replicated/duplicated
Duplicated chromosome/Genetic materials moves to opposite end of
cell/segregate
Cell grows/gets large
Each copy of duplicated chromosone attaches to a different part of the
cell membrane
Cell divides into two daughter cells/cytokinesis
New cell wall is laid down
Each daughter cell has a copy of chromosome/genetic material/is
identical to the parent
43
RNA and DNA differences
DNA contains deoxyribose sugar
RNA contains ribose sugar 1–2
DNA contains thymine
RNA contains uracil 1–2
DNA (usually) occurs in the nucleus
RNA occurs in nucleus and cytoplasm or RNA occurs in cytoplasm 1–2
DNA contains genes
RNA translates/transfers genetic code 1–2
DNA is (usually) double-stranded
RNA is single stranded 1–2
DNA is self replicating/synthesized from DNA
RNA is synthesized from DNA
44
Describe the
main features of a negative feedback mechanism.
Change in internal environment
Brings about a response/stimulus triggers a response
Receptor that senses change
Response counteracts the change/feedback alters the stimulus
Processing centre/control centre/modulator processes the
signal
Effector carries out the response/a response is carried out
45
endothermic definition
Endothermic is the term used to describe an animal that regulates
it body temperature independently of the external environment
46
ectothermic definition
Ectothermic is the term used to describe an animal whose body
temperature fluctuates with the external environment
47
Does a large body size will help a mammal to retain body heat in a cold environment?
A large body has a low surface area to volume ratio and so will lose
less body heat to the environment
48
Name the process used by a mammal to generate body heat
Metabolism/metabolic rate/respiration
49
Explain how blubber helps a marine mammal to retain body heat in cold water
Blubber insulates/prevents heat transfer (from mammal to
water)/Blubber is a poor conductor of heat
Blubber surrounds the body of the mammal
Separates warm core of body from the cold water/external
environment
Heat is retained in the core of the body
50
Many plants and animals use evaporative cooling in thermoregulation. Explain the main
principles of evaporative cooling.
Water evaporates/Changes from liquid to gas
This requires energy
This energy is taken from the plant or animal
Results in cooling
Water vapour is released from the plant or animal
51
State how infectious diseases differ from other types of diseases. (
Caused by a pathogen/organism 1
Can be transmitted from one host to another/contagious
52
Explain the main principles of herd immunity.
Large proportion of the host population become immune
Immunity can be gained naturally/by recovering from disease or
immunity can be gained artificially/by a vaccine
Limits the spread of the disease/too few susceptible individuals to
sustain the spread
Pathogens/infected hosts/infected people mainly come into contact
with immune hosts/immune people
Ultimately reduces the risk for susceptible individuals (because
disease is relatively rare)
Higher the proportion of the population that is immune, the greater the
protection
Protects (vulnerable) individuals who cannot be vaccinated
The exact proportion depends on virulence and infectivity of a
particular disease
53
Global climate change is
predicted to increase the risk of malaria transmission at higher altitudes in tropical
regions. Explain why
(Malaria is) Transferred by mosquito/Mosquito vector/Anopheles
Mosquito thrives in a warm environment/Is restricted to warm
environment or/Is rare in cooler environments/at higher altitudes
(Global climate change will) increase temperature at higher altitudes
Mosquito will spread to higher altitudes or will increase in abundance
at higher altitudes or will be more active at higher altitudes
Mosquito will take the disease with it when it spreads or people are
more likely to be bitten if mosquitoes are more abundant/more active
(Higher temperature) Will speed up the life-cycle of the
pathogen/Plasmodium/protozoan
This will increase the abundance of the pathogen
Greater abundance of pathogen, means the risk of transmission is
higher
54
Explain how a disease-causing strain of bacteria can evolve resistance to an
antibiotic used to treat the associated disease.
Affected people were treated with the antibiotics
Antibiotics killed bacteria in most individuals/cured most individuals
This halted the spread/killed off of antibiotic sensitive strains of the
bacterium
A bacterium acquired resistance to the antibiotic
Through mutation or through the acquisition of a plasmid with a
resistance gene
These resistant bacteria were unaffected by the antibiotic
The antibiotic resistant bacteria continued to be transmitted/continued
to reproduce
Therefore the antibiotic resistance bacteria are becoming more
common
Natural selection favoured the antibiotic resistance strains or the
antibiotic sensitive strains were selected against
Pathogens evolve rapidly in changing environment (antibiotic
represents a change environment).
55
List the main steps involved in producing a DNA profile for an organism.
Extract/Isolate/Obtain DNA/from organism 1
Use PCR/cloning to produce a large amount of DNA/of a particular DNA
sequence
1
Sequence DNA/use restriction enzymes to produce fragment
profile/Amplify DNA region with repeat units/VNTR/STRs 1
Use electrophoresis to visualize/separate out different pieces of DNA 1
T
56
Explain how DNA profiling could be
used to determine whether these people had contracted the virus through the dental
practice.
Create DNA profile of the virus in these patients.
Create/obtain DNA profile of hepatitis virus from other sources
Compare the DNA profiles
If patients contain same/related strains of virus, then it likely came from
the dental practice.
Use phylogenetic tree to show the relationships among the viruses
from the different sources
57
role that Restriction enzyme plays in gene cloning.
cuts (target) gene from donor organism or cuts plasmid DNA so gene can
be inserted
58
role that plays ligase in gene cloning.
binds (target) gene to plasmid DNA
59
role that plays Plasmid in gene cloning.
makes large amounts of (target) gene
60
role that plays vector in gene cloning.
introduces (target) gene to recipient organism
61
Explain an advantage of using DNA recombinant technology, rather than artificial
selection, to produce a herbicide-resistant strain of canola.
hance of finding a gene with (broad/strong/desirable)
herbicide resistance
1–2
Relatively quick
Can produce a strain within one or few generations or artificial
selection can take many generations to fix herbicide resistance in a
trait
1–2
Only manipulate herbicide resistance
Allows retention of other desirable characteristics in the strain or
artificial selection for one trait can inadvertently lead to changes in
other traits
62
Explain a possible adverse environmental effect that could result from farming
herbicide-resistant canola.
Any one set of answers, one mark per point.
Will not be able to use herbicides to kill the canola plant.
These plants could spread and become a nuisance. 1–2
Potential for the herbicide resistance gene to spread to other
species.
This could create a super weed/a nuisance plant that is resistant to
herbicide
1–2
Relatively new/Untried
Consequences are not fully understood 1–2
Over use of herbicide/increased use
Leading to evolution of herbicide-resistant weeds/death of
non-target species
63
State one way of improving the reliability of the study.
increase the sample size or use more Daphnia or repeating
experiment
64
List four features visible in the diagram above that would assist the plant in conserving
water.
stomata on lower surface
stomata in pits or sunken stomata
hairs/trichomes
cuticle (on upper surface)
multicellular/thick epidermis
guard cells
65
The root systems of xerophytes often include spreading roots just beneath the soil
surface. Outline two advantages of these surface roots for xerophytes.
Advantage 1 (large surface area of roots)
(roots) cover a large surface area
increases chances of finding water or provide anchorage
Advantage 2 (roots close to surface)
can access surface water or small amounts of water on the surface
can absorb water before it evaporates or can quickly absorb water
Advantage 3 (large volume of roots)
large volume (of roots)
more room to store water
66
Describe the method used by Agrobacterium to invade the plant host.
uses flagella to swim to plant
attracted by sugars/chemicals released by wound
(usually) invades through wounds/damaged tissue
bacteria attaches to (plant) cell
transfers (some) DNA/plasmid into plant cell
DNA (permanently) integrates into plant genome
67
Outline the role that Agrobacterium plays in the production of transgenic plants and
explain why it is well-suited to this role.
because it naturally/normally transfers DNA/genes to plants (during
disease production)
and because it can infect a broad range of host plants
this natural ability can be exploited or bacteria requires little
modification to perform this role
plasmid/DNA contains sequence for integration into plant genome
can be used to clone target DNA
68
State two similarities between binary fission and mitosis.
types of cell division
produce genetically identical cells or types of asexual
reproduction
produce two (daughter) cells
69
State two differences between binary fission and mitosis
binary fission (mainly) occurs in bacteria/prokaryotes, mitosis
occurs in (most) eukaryotes or binary fission divides cells
without a nucleus, mitosis divides cells with a nucleus
mitosis has a spindle, binary fission does not or binary fission
divides only a single chromosome type, mitosis divides multiple
chromosome types
binary fission is faster or mitosis is slower
70
Explain the role of fertilisation in sexual reproduction. (
fusion of gametes
combines genetic material from two different parents/male and female
parents/egg and sperm
meiosis produces haploid gametes or gametes with only one copy of
each chromosome type
restores diploid number of chromosomes or ensures individuals have
two copies of each chromosome type
create genetic variation/differences
71
Outline how crossing over creates genotypic variation
(crossing over) exchanges alleles between homologous
chromosomes/pairs of chromosomes
chromosomes therefore have a different/new/unique
combination of alleles (compared to those in the parent they
were inherited from)
the different/new/unique combination of alleles creates
different/new/novel genotypes
72
Outline how independent assortment creates genotypic variation
homologous chromosomes/chromosome pair separate
independently of each (during meiosis I)
form random combinations of chromosomes or a (unique) mix
of maternal and paternal chromosomes in a gamete
novel combinations of chromosomes creates
different/new/novel genotypes
73
Explain why mutation is the ultimate source of genetic variation
mutation changes DNA sequence/structure or chromosome
structure/number or permanent change in DNA
this creates new genetic/DNA variation/polymorphism or new alleles
only process that creates new/unique alleles
new/different alleles (which come from mutation) are needed to create
novel combinations of alleles/genotypes/individuals
74
Explain how such a range of variation has
arisen within domestic dogs.
artificial selection or selective breeding by humans 1
(ancestral) dogs with a desirable trait/s were selectively breed or only dogs
with desirable trait/s were allowed breed/pass on genes 1
this process was repeated over many generations 1
this resulted in a group/breed of dogs showing the desired trait/s or only
having genes/alleles for the desired trait/s 1
this happened independently for different traits resulting in breeds with
different traits or cumulative effect of breeding different variants/traits in
different lines or dogs were bred for different purposes
75
. Explain one reason why small populations are at risk of
extinction.
small populations lose genetic diversity faster than large population or
small populations have lower genetic diversity than large populations 1
due to genetic drift or random/chance loss of genetic variation 1
(under genetic drift) advantageous alleles can become rare/lost or
disadvantageous alleles can become common/fixed 1
not enough variation to resist disease or to adapt to environment/
environmental change 1
Or (ecological reason)
individuals may not be able to find a suitable mate because of unequal
sex ratio or low population density 1
this may also change/stop important social behaviour/s 1
amount of inbreeding may increase resulting in reduced fitness/increased
inbreeding depression 1
susceptible to environmental fluctuations as may lose all/most individuals
in a poor year
76
Describe how xerophytes lose water to the environment.
as water vapour or via evaporation of water or via transpiration 1
from (open) stomata (in the leaves)
77
Outline the four main steps required to produce a line
transgenic fish with increased resistance to infection by certain bacteria.
Step 1: identify gene from another organism that will confer resistance to
bacterial infection 1
Step 2: isolate target gene or make gene construct (based on that gene)
or make copies of target gene 1
Step 3: insert target gene into fish 1
Step 4: verify that fish is expressing gene or propagate
modified/transgenic fish
78
why are viruses considered non living
cannot reproduce without a host or requires host structures to
reproduce
does not have a cellular structure/cell organelles
does not produce own energy/does not respire
does not grow
79
what is a disease vector
an organism/agent that transmits a pathogen 1
into another species/type of organism (e.g. mite to bee)
80
Outline
two measures that could be used to reduce the chances of this mite becoming
established in Australia.
check/prohibit import of bees/bee products (contaminated with mite)
stop mite entering Australia
monitor bees/bee colonies in Australia for mite infestation
destroy/treat infested bees/bee colonies (before mite can spread
further)
limit movement of bees/bee colonies/bee products within Australia
infestations will remain localised
81
The diploid number of chromosomes in honey bees is 32. Queen bees are diploid and
produce eggs by meiosis. Female worker bees hatch from fertilised eggs, whereas male
bees hatch from unfertilised eggs. How many chromosomes will occur in male bees?
Explain your answer.
16 1
haploid number of chromosomes or half the number of diploid
chromosomes or meiosis halves the (diploid) chromosome number 1
same number of chromosomes as unfertilised egg 1
the male parent does not contribute any chromosomes or only the female
parent contributes chromosomes
82
Explain comparative genomics and how it can lead to an in-depth understanding of plant
evolution.
comparison of the entire genomes of different species/groups 1
used to identify all similarities/differences between different species/groups 1
and genes/DNA sequences that are unique particular groups or that
control particular traits 1
(can use the information to) deduce evolutionary relationships or when
traits evolved or how traits have changed over time
83
Explain bioinformatics and why it is important to the field of comparative genomics
science of analysing large/complex data sets in biology
multidisciplinary or applies computers/mathematics/statistics to the
study of problems in (molecular) biology
involves the development of software or storage/analysis of
biological/molecular data
Importance to comparative genomics
comparative genomics produces very large data sets 1
specialised computing/analyses provided by bioinformatics is needed to
store/analyse such large data sets or traditional methods for analysing
genetic data are not capable of storing/analysing such large data sets
84
Explain how structure can prevent the spread of jarrah dieback.
disease is spread (from plant to plant) by spores/zoospores
spores/zoospores are more active when it is wet
vehicles pick up more (contaminated) soil when it is wet; (therefore) risk of transmission/spread is greater when the soil is wet
vehicles can spread disease/spores/zoospores over a large area
85
Describe how the tuberculosis pathogen is transmitted to a new host.
pathogen is in air/airborne or affected individuals breathe out
pathogen/droplet
new host breathes in/inhales pathogen
86
Describe the impact that the tuberculosis pathogen has on the host.
infects lungs/respiratory system
* causes coughing/lung irritation/breathing problems/tuberculosis
* sometimes does not cause symptoms or takes time for
symptoms to develop or can infect brain/nervous system/tissue
other than the lungs
87
Explain how vaccination helps to control the spread of tuberculosis.
vaccination introduces weakened/harmless version of a pathogen into
body
* this stimulates production of antibodies/stimulates an immune
response
* vaccinated individuals become immune or do not catch the disease
* higher the proportion of the population that is immune, the greater the
protection or the converse
* because infected individuals do not/rarely come into contact with
susceptible individuals or the converse
* herd immunity/high immunity protects susceptible individuals
88
When travellers enter Australia from overseas, they are required to declare all plant and
animal matter that they have brought with them. Explain why
quarantine/biosecurity measure
* protects agricultural industry/the environment or stops spread of
disease
* stops the introduction of exotic pests/diseases/weeds found in other
countries (but not in Australia)
* plant and animal matter/declared items may carry pests/diseases
* plant and animal matter found to be infected will either be treated with
pesticides/insecticides or destroyed
89
Population dynamics
study of changes in population size or of how and why populations
change size or of size and age composition of populations
90
Biogeography
study of the geographical distribution of organisms/species/
communities
91
Reproductive behaviour
behaviour associated with mating or rearing young
92
Describe two ways in which captive breeding can assist in the recovery of
wild populations.
release genetically diverse individuals to
* boost/maintain genetic diversity (of wild populations) 1–2
Subtotal 2
* release additional/large numbers of individuals to
* boost population size
93
Explain how gene flow affects the gene pool of a population.
gene flow is the exchange of genetic material/alleles between
populations
* gene flow/migrants/immigrants can bring new alleles into the gene
pool/population
* because they come from populations with different alleles
* gene flow/migrants/immigrants can change allele frequencies in the
allele in the gene pool/population
* because they come from populations with different allele frequencies
* gene flow/migrants/immigrants reduce differences between the gene
pool of the source and recipient populations
94
List four reasons why the fossil record is incomplete.
only hard parts are likely to form fossils or soft parts are unlikely to
form fossils
* only organisms that avoid decomposition/scavengers/predators form
fossils or fossils only form in areas with no oxygen/bacteria
* only organisms that are buried in sediment/mineral rich water form
fossils or rapid burial
* not all fossils have been found yet
* some fossils have been destroyed (by volcanic eruptions/human
activities/earthquakes)
95
Explain how differences in the amino acid sequence of a protein can provide evidence
of evolutionary relationships between organisms.
sequence of amino acids in a protein is determined by a DNA
sequence
* the more similar the amino acids, the more similar the DNA sequence
* organisms with similar DNA/amino acid sequences are closely related
* because they diverged more recently
* less time to accumulate mutations/differences
96
explain direct contact
physical contact with infected organism, transfer is via bodily fluids.
97
explain indirect contact
via a reservour or contaminated object, not through physical contact with an infected organism
trasnsfer can be via airbourne patticles, contaminated water or food and vectors.
98
importance of vaccination
large portion of the population (~%90) becomes immune through the vaccination
immunised individuals do not usually produce symptoms is exposed to the disease/ pathogen
transmission/spread of pathogen from person to person is restricted
most of the community is protected from illness, not just those who are immunised.
99
function of mRNA
carry the transcribed code from DNA / a gene from nucleus
to the ribosome for translation into a polypeptide
100
function of tRNA
carries correct amino acid to ribosome
anticodon binds to complementary mRNA codon (in the ribosomes)
101
explain why more than one molecule of a particular protein can be synthesised from a single transcribed mRNA molecule
mRNA is a template
mRNA can be reused multiple times/recycled
new amino acids are used to synthesise more proteins
102
DNA polymerase function
adds free nucleotides to build leading strand (towards replication fork)
103
DNA helicase function
unwinds and separates the DNA double helix
104
why cant marine fish survive in freshwater
the tissues of the marine fish are hypertonic compared to freshwater
water will be absorbed/will enter fish via osmosis
internal salt/ion concentration decreases cell concentration
affecting normal cellular activities/ the cells burtst due to excess water uptake.
105
difference between endotherm and an ectotherm
an endotherm maintains a constant internal body temperature via metabolic activity
an ectotherm has a fluctuating internal body temperature that is controlled by extrenal/ internal heat sources.
106
benefits of being ectothermic
lower energy consumption/requirements
less food required
more energy available for growth and reproduction
107
how does blubber work in thermoregulation?
provides a layer of insulation
prevents heat loss via radiation
108
how does counter-current heat exchange work in thermoregulation?
adjacent arteries and veins in the limbs/extremities lie in close proximity
allows for conductive heat exchange between warm arterial blood (from heart) to cooler venous blood (from extremities)
109
how does vasocontriction work in thermoregulation?
capillaries in the extremities/skin are constricted to reduce blood flow
warm blood is retained in the core of the body/not lost to external environment
110
biotechnological process required for each of the following
DNA fingerprinting
determining the ancestral relatedness between species
synthesis of large volumes of DNA
measuring expression levels of a disease-causing gene
DNA fingerprinting
gel electrophoresis
determining the ancestral relatedness between species
molecular hybridisation
synthesis of large volumes of DNA
polymerase chain reaction (PCR)
measuring expression levels of a disease-causing
gene
microarray
111
define short tandem repeat
a short section of non-coding DNA
that repeats the same nucleotide sequence over and over.
112
why are STRs used in DNA profiling
many different STRs are present in the humanb genome
STRs are highly variable between people (in length and in composition)
equivalent STRs can be easily isolated from DNA samples and compared to determine similarities/differences.
113
define transgenic organism
an organism with DNA from another species inserted into its genome
114
two characteristics of bacterial plasmids that make them useful as gene vectors
antibiotic resistance gene
independant replication/ self-replicating
readily transferred between cells
115
an example of agricultural biotech
ready roundup canola - contained herbicide (glyphosate) resistant gene so weeds can be sprayed without harming canola crop.
116
Explain how DNA profiling could be used to determine whether the individuals infected on the cruise ship had contracted the virus
Obtain samples of the virus from each infected passenger.
Obtain samples of virus from other sources/countries from where other passengers originate.
Create DNA profiles of the virus samples using gel electrophoresis.
Make a comparison of all the profiles sampled.
If the infected passengers have the same virus profile as the Sydney passenger and sample from Sydney, the virus likely came from this source.
117
Outline four different ways in which antibiotics can control and/or eliminate a bacterial infection.
* Rupture bacterial cell membrane.
* Inhibit cell wall synthesis.
* Inhibit protein synthesis.
* Inhibit reproduction of nucleic acids/DNA.
* Interfere with metabolic reactions.
118
Identify the mode of reproduction of bacteria and explain how it allows for exponential pattern of growth.
Binary fission
Asexual reproduction with simple mitotic division producing two daughter cells.
Cells (and then daughter cells) can divide very rapidly (every 10 - 15 hours).
119
Identify two adaptations of halophytes that enable control of their internal salt concentration and osmotic potential.
* Salt bladders on leaf hairs to excrete salt.
* Sequestering salt ions in leaf vacuoles.
* Shedding old, salt-filled leaves.
* Specialised root tissue that prevents entry of salt.
* Salt glands to excrete salt.
* Mechanism to return excess leaf and stem salt to roots.
120
Explain how natural selection could have influenced the evolution of legless lizards
A mutation affecting limb growth appears in the gene pool, introducing new genotype and phenotypes.
Lizards expressing the new mutation (phenotype) have an advantage in their habitat. E.g. can hide more effectively from predators.
Lizards with the new phenotype survive in large numbers.
These lizards reproduce, giving rise to offspring carrying alleles for the mutation/expressing phenotype. Over time the trait is passed down and becomes more exaggerated (legs become smaller).
Lizards with reduced leg size exploit a niche not available to lizards with 'normal' legs. E.g. hiding in sand from predators and feeding on soil fauna.
Lizards only mate with other legless lizards present in the new niche. Reproductive isolation occurs which leads to formation of a new species.
121
disadvantage of being an ectothermic animal
* Vulnerable to predation when accessing heat or have low energy levels.
* Cannot inhabit cold environments.
* Require specialised adaptations to thermoregulate.
* Require specialised adaptations to control water balance.
122
structural adapation for ectotherms
* High surface area to volume body shape - allows rapid heat absorption via conduction (warm surfaces), radiation and convection (warm air).
123
how does chytrid affect Osmoregulation
* Reduced water uptake through skin into the body.
* Altered osmotic gradient for cellular uptake of water (osmosis).
* Dehydration of cells/cell lysis as water cannot be taken up via osmosis.
* Less water available for cellular respiration so less energy produced.
124
how does chytrid affect Gas exchange
* Reduced exchange of metabolic gases (O2 and CO2) through the skin.
* CO2 levels in blood increase and O2 levels decrease - frog lungs are not adequate to cope with increased requirements.
* Cellular respiration decreased as cells are starved of O2 - less energy produced.
* Diffusion gradients for gases affected as CO2 builds up in the blood.
125
Define virulent.
The ability to cause disease in a host/individual.
126
Discuss the effect of this outbreak on the population's gene pool. (the effect of disease on a gene pool)
Sudden random reduction in population will decrease diversity of the gene pool and it cannot be recovered.
Gene pool of resulting population will not be representative of the original population - bottleneck effect.
Deleterious genes may be preserved in the gene pool by chance and have a detrimental effect on the future population of frogs.
Inbreeding may occur with reduced numbers, causing a further decrease in genetic diversity.
127
Explain one factor that could further increase the threat of extinction of one infected species of frog over another.
* Small population size - small populations have lower genetic diversity and therefore more likely to face extinction.
* Fragmented habitats - populations living within a fragmented habitat will suffer a loss of diversity as gene flow is reduced.
* Climate change - frogs inhabiting ecosystems that are less resilient to the effects of climate change will more likely suffer loss of diversity.
128
Explain why optimal cellular function is dependent on the maintenance of a constant internal environment.
* Biochemical reactions can only occur under specific internal conditions or within certain limits. If these conditions are not maintained, then vital metabolic reactions cannot occur.
129
Describe two different types of homeostatic receptors present in an organism.
* Photoreceptors - light/infra-red.
* Mechanoreceptors - pressure/sound/gravity.
* Chemoreceptors - pH (H+)/oxygen/ions/carbon dioxide.
* Thermoreceptors - temperature/hot and cold.
130
(f) Explain how an mRNA molecule carrying an incorrect code can lead to the synthesis of a non-viable protein.
Any mutation or error in this specific sequence of codons of an mRNA molecule will be translated in the ribosome during synthesis of the polypeptide.
Every codon in the mRNA molecule codes for a specific amino acid that must be added in a specific sequence.
Amino acids are carried by the transfer RNA molecules (tRNA) that have an anti-codon sequence complementary to mRNA.
An incorrect codon within the mRNA will result in the delivery and addition of the incorrect amino acid to the growing polypeptide chain.
A polypeptide with incorrect amino acid sequence cannot be packaged into its specific 3D shape, will have no active site and therefore be non-functional.
131
Explain two benefits of non-shivering thermogenesis to the survival of the Patagonian leaf-eared mouse.
* Saves energy - no shivering/contraction of skeletal muscles so ATP/energy is conserved for other cellular functions.
* Reduces oxygen requirements - much less oxygen is needed by muscle cells as they are not respiring for heat production.
* Water conservation - lower rate of cellular respiration in muscle cells for thermoregulation results in lower water requirements and aids osmoregulation.
132
Define the term ‘pandemic’
Outbreak of a particular infectious disease (1) throughout the world (1)
133
Explain why is it still possible for a Cholera pandemic to occur in the future.
Travel from infected to non-infected areas.
Extreme weather events from climate change becoming more frequent.
Continuing lack of treatment in susceptible areas.
134
Explain how pathogens like this can become resistant to antibiotic treatment
Antibiotics are overprescribed for prevention and not treatment.
Natural selection ‘chooses’ phenotypes in bacteria that resist antibiotics.
Bacteria reproduce and mutate very rapidly allowing for new strains to
evolve.
135
Define the term ‘bacterial plasmid’
Small, circular DNA molecule separate from chromosomal DNA.
Can replicate independently of rest of bacterial cell.
136
Outline three (3) major developments in agriculture as a result of recombinant DNA technology.
Herbicide resistance – insertion of gene that causes crop species to be unaffected by chemical herbicides such as Round-up®.
Farmers can spray their crops for weeds without killing crop plants.
Insect resistance – reduce time and money spent by farmers spraying crops with insecticides.
No residual chemicals on food bought by consumers.
Drought tolerant plants – require less water and/or irrigation. Beneficial for farmers in areas that are becoming increasingly dry due to climate change.
Increased concentration of vitamins in food – gene that codes for the desired nutrient is spliced into the organisms DNA.
This plant or animal will produce more of this nutrient and therefore the food source is enriched.
137
Describe two (2) possible negative effects on the environment as a result of the production of genetically modified crops.
* Seeds from modified species spread to other properties or bushland.
* GM plants could then infest neighbouring paddocks that do not grow GM plants or are organic producers/Lose organic status.
* Overuse of herbicides on resistant crops (eg., Round-up® Ready).
* May affect plants on adjacent properties that are not GM or in natural environment
* May stimulate evolution of ‘superweeds’
* Could pollute soil and water sources.
138
Explain how biotechnology has helped improve the conservation of endangered species bred in captivity.
* Can determine the genetic variability of a species to avoid inbreeding.
* Help increase diversity of the gene pool.
139
Explain why the removal of metabolic wastes from an organism is essential for continued metabolic activity.
Toxic to cells
Change pH of blood and fluids, enzymes may denature.
Metabolic reactions slow down in response.
140
Describe the structure of the kidney from a desert marsupial and explain how this structure enables the marsupial to produce concentrated urine.
Long loop of Henle.
Medulla is thicker than cortex so more of the nephron is within medulla.
Salt gradient more extreme due to thicker medulla.
More water reabsorbed by osmosis due to high salt concentration in extracellular fluid.
141
Identify three (3) main reasons for constructing a phylogenetic tree in studies of evolutionary biology.
Shows inferred evolutionary relationships between organisms.
Illustrate historical evolution (in a structured manner) and relative time frame since last shared common ancestor.
Depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor.
142
Describe the difference between distantly related and closely related organisms in terms of their DNA sequence.
Closely related organisms share more DNA base pair matches than those distantly related. 1
DNA sequences encoding the proteins responsible for functions that were;
* conserved from the last common ancestor, should be
* preserved in contemporary genome sequences.
143
Describe the difference between distantly related and closely related organisms in terms of their Position on a phylogenetic tree.
The more closely related organisms have branches that are closely positioned and have a more recent shared common ancestor.
Distantly related organisms are on separate branches (clades) that have separated much earlier in evolutionary history and more time has passed since sharing a common ancestor.
144
Identify two (2) different ways that genetic variation can be increased as a result of sexual reproduction.
Crossing over (meiosis) of genes/DNA.
Independent assortment (meiosis) of alleles.
Fertilisation with random gametes.
145
Identify two different adaptations for water-balance in xerophytes and explain how these adaptations enable their survival.
Hairs on leaves
Reflects sun’s heat, reducing temperature and evaporation.
Waxy leaves
Prevents water loss from leaf surface.
Long narrow leaves
Reduced surface area exposed to sun.
Reduced leaf size / leaves as needles or spikes
Less surface area exposed to sun and less water loss via evaporation.
Reduced number of stomata
Fewer pores enables plant to retain more water/reduces water loss.
Sunken/recessed stomata
Creates humid micro-environment which reduces water loss from transpiration.
Stomata on leaf underside
Reduces rate of evaporation from upper leaf surface.
Stomata closure in midday sun
Stops water loss when transpiration would be greatest.
146
Which biotechnological process could be used to establish the genetic relationship between a fossilised and living plant species?
Molecular hybridisation or DNA hybridisation
147
molecular hybridisation steps
DNA is extracted from species being compared and cut into short fragments (600 -700 base pairs)
DNA fragments are heated until the helix separates into single strands (melting).
Temperature of melting is approximately 80 – 90oC.
Both species ‘melted’ DNA is combined and allowed to cool.
Single strands of DNA anneal – fragments from each species recombine with each other or hybridise to form new double strands of DNA.
Hybridised fragments are reheated to measure the temperature at which melting of new bonds occurs.
148
Explain how the genetic relatedness between two different species is measured using the results from this process.
A measure of the heat /temperature required to separate new hybrid DNA is a measure of genetic relatedness.
The lower the temperature required to dissociate the DNA strands, the fewer the bonds and lower degree of relatedness.
The higher the temperature required (closeness to original melting temperature) indicates close genetic relatedness.
149
Identify two human behaviours that can decrease the risk of contracting or spreading a contagious disease. (2 marks)
* Not sharing needles when using illicit drugs.
* Using appropriate protection during sexual intercourse.
* Washing hands after using the toilet and before food preparation.
* Staying quarantined when ill.
150
Differentiate between the terms endemic, epidemic and pandemic.
An endemic is when a disease occurs within a population at a steady rate.
An epidemic occurs when the disease begins to increase in the population above what is considered normal.
A pandemic occurs when an epidemic spreads across many countries or continents throughout the world.
151
Explain the concept of ‘herd immunity’.
When a large proportion of the population are immunised so the few left unimmunised cannot sustain the disease.
The chance of coming into contact with an infected person is very low and the disease cannot spread.
152
Outline three different ways in which bacteria cause disease.
* Divide rapidly, damaging tissues directly.
* Production of toxins that disrupt cell function.
* Pathogenic parts of bacteria stimulate an overly strong and damaging immune response.
* Interfering with the host’s immune system, increasing the susceptibility to infection by other pathogens.
153
adaptations
(i) Large, thin, vascular ears – structural.
(ii) Slim forearms that are licked and covered with saliva – structural and behavioural.
(iii) Waterproof layer of fur over thick ‘fluffy’ layer – structural.
154
explain em
* Highly vascular, thin ears allow excess heat to be removed readily from the body (vasodilation).
* Blood supply can also be restricted (vasoconstriction) to maintain warm blood with the animal’s core.
* Kangaroos are known to lick their thin forearms, which have blood vessels very close to the skin surface.
* As air passes over the wet surface it cools the skin and blood, which is circulated around the body.
* Thick, ‘fluffy’ fur and a waterproof coat.
* Fur acts as an insulator against the cold water and the waterproofing prevents the animal getting wet fur and cold skin.
155
Differentiate between gene flow and genetic drift.
Gene flow is the transfer of alleles or genes from one population to another.
Genetic drift is a mechanism of evolution in which allele frequencies of a population change (1) over generations due to chance (1). Genetic drift occurs in all populations but its effects are strongest in small populations(1).
156
Describe the process of genetic cloning.
* A cell is taken from the DNA sample from an adult Thylacine.
* A donor egg cell is removed from a related species (eg: Tasmanian devil).
* The DNA from the Thylacine is then transferred to an egg cell whose DNA has been removed.
* The egg cell is “activated” using an electrical shock and the egg cell begins dividing as if it was fertilized.
* An embryo results, this embryo is then transferred to the uterus of a surrogate female of a related species (eg: Tasmanian devil).
* After gestation is complete, the surrogate will give birth to the clone, which is a genetic copy of the animal from which the original cell was taken.
