Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology > Genetics, Biodiveristy And Classification > Flashcards

Genetics, Biodiveristy And Classification Flashcards

1
Q

How is DNA stored in Eukaryotic cells?

A
  • Linear DNA that exist as chromosomes, each made up of one long molecule, found in the nucleus
  • DNA is wound around proteins called histones
  • DNA and the histones are coiled up very tightly to make a compact chromosome
  • Mitochondria and chloroplast in eukaryotic cells also have their own DNA, which is circular and shorter.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How is DNA stored in Prokaryotes?

A
  • Also carried as chromosomes, but are circular and shorter
  • condenses to fit in by super coiling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a gene?

A

A sequence of DNA bases that codes for either a polypeptide or a functional RNA.

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

What is a genome?

A

The complete set of genes in the cell

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

What is a proteome?

A

The complete set of proteins a cell is able to produce

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

What is a non-coding repeat?

A

Regions of multiple repeated DNA outside of genes
E.g. CCTTCCTTCCTTCCTT they do not code for amino acid alongside introns

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

What is an allele?

A

Different forms of a gene, where the order of bases in each allele is slightly different so they code for slightly different versions of the same polypeptide

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

What are homologous pairs?

A

Pairs of matching chromosomes, they both are the same size and have the same genes, although they can carry different alleles, alleles coding for the same characteristic will be found at the same fixed position (locus) on each chromosome.

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

What is mRNA?

A

Made during transcription = messenger RNA
Carries the genetic doe from the DNA to the ribosomes, where it is used to make a protein during translation
- mRNA is a single polynucleotide strand, groups of three adjacent bases a called codons

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

What is tRNA?

A

tRNA is involved in translation
It carries the amino acids that are used to make proteins to the ribosomes
- tRNA is a single polynucleotide strand that is folded into a clover shape held to tether by hydrogen bonds
- every tRNA molecule has a specific sequence of three bases at one end called an anticodon
- they have an amino acids binding site

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

What happens during transcription?

A

1) DNA helicase breaks the hydrogen bonds between the two strands, exposing them to bases
2) RNA polymerase joins free nucleotides to the exposed bases, complementary base pairings means that the mRNA strand ends up being a complementary copy of the DNA template;ate strand, except the base T is replaced with U
3) hydrogen bonds reform and the strands coil back into a double helix
4) when RNA polymerase reaches a stop code it detaches from the DNA
5) mRNA three modes out of the nucleus through a nuclear pore and attaches to a ribosome in the cytoplasm

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

What happens during splicing?

A

Introns are removed leaving the exons joined together
Prokaryotic mRNA doesn’t have introns so no splicing necessary

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

What is the process of translation?

A

1) mRNA attaches itself to a ribosome and tRNA molecules carry amino acids to it, ATP provides the energy for the bond between the amino acids and the tRNA to form
2) tRNA with an anticodon that’s complimentary to the first codon on the mRNA attaches itself to the mRNA
3) a second tRNA molecule attaches itself to the next codon
4) the two amino acids are joined by a peptide bond
5) this continues all along the mRNA until a stop codon is reached

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

Why is the genetic code non-overlapping?

A

Each base triplet is read in sequence, superstate from the triplet before it and after it, bases don’t share their bases

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

How is the genetic code degenerate?

A

There are more possible combinations of triplets than there are amino acids, means that some amino acids are coded for by more than one base triplets

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

How is the genetic code universal?

A

The same specific base triplets code for the same amino acids in all living things

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

What are gametes?

A

Sperm and eggs cells (haploid) that fuse together in fertilisation to form a zygote (diploid) which develops into a new organism

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

What does haploid and diploid mean?

A

Haploid = only one copy of each chromosome
Diploid = each cell contains two of each chromosome, one from the mum and one from the dad

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

How can fertilisation cause genetic variation?

A

Fertilisation is random as it produces zygotes with different combinations of chromosomes to both parents, the mixing of the genetic material increases the genetic diversity within a species

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

What is the general process of meiosis?

A

1) before meiosis starts the DNA unravels and replicate = two copies of each chromosome called chromatids
2) DNA condense to got double-armed chromosomes made form two sister chromatids joined by a centromere
3) meiosis 1 the chromosomes arrange themselves int. homologous pairs which are then separated halving the chromosome number
4) meiosis 2 the pair of sister chromatids that make up each chromosome are separated, the centromere is divided
5) 4 haploid cells are made genetically different from each other

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

How does crossing over create genetic variation in meiosis?

A

During meiosis 1:
- homologous pairs of chromosomes pair up
- the chromatids twist around each other and bits of the chromatids swap over
- chromatids still contain the same genes but now have a different combination of alleles

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

How is genetic variation caused by independent assortment in meiosis?

A

When homologous pairs are separated in meiosis 1 it is completely random which chromosome from each pair ends up in which daughter cell

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

Compare the outcomes of meiosis vs mitosis?

A

Mitosis = cells with the same number of chromosomes as the parent cell, daughter cells are genetically identical, two cells
Meiosis = cells with half the number of chromosomes, genetically different, four cells produced

24
Q

What is non-disjunction?

A

When chromosomes fail to separate properly
Can happen in meiosis 1 or 2
E.g. non-disjunction of chromosomes pair 21 can lead to Down Syndrome

25
What is substitution mutations and what are the outcomes?
One base is substituted for another e.g. ATGCCT becomes ATTCCT - either could code for a different amino acid - as the genetic code is degenerate = could be a different codon that still codes for the same amino acid = no effect on protein made - could be substituted for the same base = no effect - could code for a stop codon
26
What are addition and deletion mutations and what are their outcomes?
Deletion = one base is deleted e.g. ATGCCT becomes ATCCT Addition = one base is added e.g. ATGCCT becomes ATGGCCT - frame shift due to non-overlapping - changes the number of bases so it will change the base codons for the rest of the sequence after the mutation - could result in non-function protein, or an unfinished protein
27
What are mutagenic agents?
UV light, ionising radiation, some chemicals and some viruses increase the likelihood of mutations
28
How is genetic diversity increase within a population?
- mutations in the DNA forming new alleles - different alleles being introduced into a population when individual migrate form other population and reproduce = gene flow
29
What is a genetic bottleneck?
When an event that causes a big reduction in a population e.g. when a large number of organisms within a population die before reproducing - reducing the number of different alleles in the gene pool and so reducing genetic diversity - the remainders reproduce to create a larger population again with less genetic diversity E.g. Northern Elephant Seals = hunted, reduced to 50 seals
30
What is the founder effect?
When just a few organisms from a population start a new colony and there are only a small number of different alleles in the initial gene pool - frequency of each allele in the new colony may be very different to the frequency of those alleles in the original population could lead to an unfavourable characteristic being more common in the colony = higher incidence of genetic disease - can also occur as a result of migration = geographical separation
31
What is the process of natural selection?
- mutation occurs resulting in an allele that makes an individual better adapted to their environment - individuals with the beneficial allele are more likely to survive and reproduce, outcompeting others - they will reproduce and pass on the favourable allele on to further generation - the frequency of the allele increases
32
What are behavioural adaptations?
Ways an organism acts that increases its chance of survival and reproduction e.g. possums playing dead
33
What are physiological adaptations?
Processes inside and organisms body that increases its chance of survival e.g. brown bears hibernating over winter, lowers their rate of metabolism, conserving energy so they do not need food over this time of year
34
What are anatomical adaptations?
Structural features of an organisms body that increases its chance its chance of survival e.g. whales have a thick layer of blubber to keep warm
35
What is directional selection?
Where individuals with alleles for characteristics of an extreme type are more likely to survive and reproduce - could be in response to an environmental change - e.g. antibiotic resistant bacteria, some individuals in bacterial population are resistant to antibiotics and so survive and reproduce after some time the majority of the population carries the antibiotic allele
36
What is stabilising selection?
Where individuals with alleles for characteristics towards the middle of the range are more likely to survive and reproduce - occurs when the environment isn’t changing, reduces range of possible characteristics - e.g. human birth weight
37
What is the aseptic technique for testing the effects of antibiotics using agar plates?
1) use a sterile pipette to transfer the bacteria from the broth to an agar plate, spread the bacteria over the plate using a sterile pipe plastic spreader, clam-shell method 2) use sterile forceps to place paper discs soaked with different antibiotics spaced apart on the plate, and a control disc 3) lightly tap lid on and invert and incubate for 48 hours, anywhere that the bacteria has grown is called the zone of inhibition 4) size of an inhibition zone tells you how well and antibiotic works - work near a Bunsen flame - flame the neck of the broth after it is opened and just before it is closed
38
What is phylogeny?
The study of the evolutionary history of groups of organisms, telling us who is related to whom and how closely related they are
39
What is taxonomy?
The science of classification, it involves naming organisms and organising them into groups - there are eight levels of groups called taxa Domain, kingdom, phylum, class, order, family, genus, species
40
What is the binomial naming system?
Genus and then the species e.g. Homo Sapiens
41
What is courtship behaviour?
Carried out by organisms the attract a mate of the right species E.g. releasing chemicals, or a series of displays Can be used too: - identify a mate - attract a mate - see if a mate is sexually mature
42
Why is courtship behaviour species specific?
Only members of the same species are too recognise each other and breed, preventing inter-breeding - can be used too classify organism - the more closely related species are the more similar their courtship behaviour is
43
What is genome sequencing?
Entire base sequences of an organism’s DNA can be determined, which can then be compared to the DNA base sequence of another to see how closely related they are. - closely related species will have a higher percentage of similarity in their DNA base order
44
What is comparing amino acid sequences?
Related organisms have similar DNA and so similar amino acids sequences in their proteins - the more similar the amino acid sequence is the more closely related the different species are
45
What is immunological comparison?
Similar proteins will also bind the same antibodies E.g. antibodies of a human protein are added to isolated samples from other species, if a species is closely related it may recognise the same antibodies
46
Ho can gene technologies measure genetic diversity directly?
- different alleles of the same gene will have slightly different DNA base sequences, comparing the DNA base sequences of the same gene in a different organism in a population allows a scientist to find out how many alleles of that gene a population has - different alleles will has produced slightly different mRNA base sequences, and may produce protiens with slightly different amino acid sequences
47
What is variation?
The differences that exist between individuals, variation between species and within species - can be caused by genetic factors, different species have different genes, individuals of the same species have the same genes, but different alleles - can be caused by the environment e.g. climate, food, lifestyle
48
What is biodiversity?
The variety of living organisms in an area at one time
49
What is a habitat?
The place when an organism lives
50
What is a community?
All the popular towns of all the different species living in the same areas at the same time
51
What is local biodiversity?
The variety of different species living in a small habitat that is local e.g. a garden or pond
52
What is global biodiversity?
The variety of species on earth
53
How can biodiversity be measured?
Using simpsons index - the higher the number, the more diverse the area is
54
What is species richness?
A measure of the number of different species in a community, can be worked out by taking random samples of community and counting the different number of species
55
What agricultural practises reduce biodiversity?
- woodland clearance for farmland - hedgerow removal for large machinery - pesticides kills detritivores and pests and the predators of the pests - herbicides kills pest plants and species that feed on the plants - monoculture single species
56
What are some examples of conservationist schemes?
- legal protection of endangered species - SSSIs special sites of scientific interest - the Environmental Stewardship Scheme = encourages farmers to conserve biodiversity

Biology (9 decks)

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