Brainscape's Knowledge GenomeTM

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


See full index

biology year 12 > topic four > Flashcards

topic four Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

what do DNA and RNA do (comparison)

A
  • DNA holds genetic info whereas RNA transfers the genetic info from DNA to ribosomes.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the genetic code

A

the order of bases on DNA

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

what does each triplet of bases code for

A

a particular amino acid (known as a codon)

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

what is a gene

A

a sequence of DNA which codes for either a polypeptide or functional RNA

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

what is a locus

A

the location of a gene

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

what are the non-coding sections of DNA called

A

introns

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

what are the coding regions called

A

exons

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

how many possible combinations of the triplets are there

A

64 (4^3) - means each amino acid is represented by more than one triplet

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

features of the genetic code

A
  • non overlapping
  • degenerate
  • universal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does non overlapping mean

A

each triplet is only read once and odes not share any bases

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

what does degenerate mean

A

there are more possible combinations of triplets than there are amino acids (64 comb, 20 AA)

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

what does universal mean

A

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
13
Q

DNA in eukaryotes

A
  • long
  • linear
  • has introns
  • has histones (proteins)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

DNA in prokaryotes

A
  • short
  • circular
  • no introns
  • no histones (proteins)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how many chromosomes does a human have

A

46 (23 pairs) - arranged into homologous pairs

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

what is a homologous pair

A

consists of 2 chromosomes that carry the same gene, but have a different allele (therefore not identical)

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

which chromosome determines the sex of an individual

A

23

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

what is an allele

A

an alternative form of a gene

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

what are the two stages of protein synthesis

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

where does transcription occur and what does it involve

A
  • occurs in nucleus
  • involves DNA and mRNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

where does translation occur and what does it involve

A
  • occurs at ribosome
  • involves mRNA and tRNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

mRNA summary

A
  • made during transcription
  • carries genetic code from DNA to ribosomes
  • single polynucleotide strand
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

tRNA summary

A
  • involved in translation
  • carries amino acids to ribosomes
  • single polynucleotide strand
  • H bonds between base pairs
  • every molecule has an anitocodon
  • has amino acid binding site at the other end
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

transcription

A

1, an enzyme causes hydrogen bonds between bases to break. DNA uncoils and separates the two strands
2. one of the strands is used as a template to make the mRNA molecule (template called antisense strand)
3. free nucleotides line up, joined by phosphodiester bonds, forming a molecule of mRNA. when stop codon is reached, this ends. as RNA polymerase moves away, DNA reforms
4. in eukaryotes, DNA is then spliced to remove introns. mRNA then moves out of nucleus through a pore and attaches to a ribosome in cytoplasm

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

translation

A
  1. mRNA attaches to ribosome and tRNA collects amino acids from cytoplasm and carries them to ribosome.
  2. tRNA attaches itself to mRNA by complementary base pairing
  3. amino acids attach to two tRNA molecules by a peptide bond and tRNA molecules then detatch themselves from amino acids, leaving them behind
  4. process is repeated to form a polypeptide chain until a stop codon is reached. protein synthesis ends.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is a mutation

A

a change in the base sequence of DNA

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

what are the three types of mutation called

A
  • addition
  • substitution
  • deletion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is substitution

A

where one of the bases is replaced by another
least harmful

29
Q

what is addition

A

where a base is added to the sequence, causes a frame shift, very serious

30
Q

what is deletion

A

when one of the bases is removed, causes a frame shift, all bases shift to the left, very serious

31
Q

what are the two types of chromosomal mutations

A
  • polyploidy
  • non-disjunction
32
Q

what is polyploidy

A

changes occur in the whole set of chromosomes - individual could have 3 sets instead of 2

33
Q

what is non-disjunction

A

when chromosomes fail to separate correctly in meiosis. as a result, gametes will have one more or one less chromosome.

34
Q

what disability can come as a result of non-disjunction

A

downs syndrome - extra chromosome 21

35
Q

what does meiosis produce

A
  • haploid
  • 4 daughter cells
  • genetically different
36
Q

what are the two types of variation in chromosomes

A
  • crossing over of chromatids
  • independant segregation of homologous chromosomes
37
Q

what is the crossing over of chromatids

A
  • when chromatids twist over eachother and bits of chromatids swap over
  • same gene different combination of alleles
38
Q

what is the independant segregation of homologous chromosomes

A
  • homologous pairs line up in different orders
39
Q

what happens at stage one of meiosis

A
  • homologous chromosomes pair up
  • the cell then divides whereby each daughter cell contains one chromosome from each homologous pair
40
Q

what happens during meiosis two

A
  • chromatids of each chromosome are separated producing 4 haploid daughter cells
41
Q

what is genetic diversity

A

the total number of different alleles of genes in a species or population

42
Q

what is high diversity

A
  • having plenty of alleles in a population
  • this makes them able to adapt to changes in their environment
  • PREVENTS INBREEDING
43
Q

what is low diversity

A
  • can be beneficial
  • plants will look similar
  • asexual reproduction produces clones faster
44
Q

what is natural selection

A

the process in which fitter/more adapted individuals survive and pass on their advantageous alleles to future generations

45
Q

what is evolution

A

the process by which the frequency of alleles in a gene pool changes over time as a result of natural selection

46
Q

what are the two types of selection

A
  • directional selection
  • stabilising selection
47
Q

what is directional selection

A
  • when the environmental conditions change and the phenotypes best suited are more likely to survive
  • produce offspring
  • mean of pop. moves into the direction of these individuals
    -EXAMPLE OF THIS = ANTIBIOTIC RESISTANCE
48
Q
A
49
Q

what is stabilising selection

A
  • the phenotypes with successful characteristics are preserved and those of greater diversity are reduced
  • this selection doesnt occur due to changes in the environment
  • if env. stays the same, then individuals closest to mean are favoured because they have the alleles that have given them the survival advantage
    -EXAMPLE OF THIS = NEWBORN BABIES WEIGHTS
50
Q

what are the three types of adaptations

A
  • physiological adaptations
  • behavioural adaptations
  • physical adaptations
51
Q

what are physiological adaptations

A
  • processes inside the organisms body that increase its chance of survival
  • EXAMPLE = REGULATION OF BLOOD FLOW THROUGH SKIN
52
Q

what are behavioural adaptations

A
  • changes in behaviour that improve the organisms chance of survival
  • EXAMPLE OF THIS = MATING CALLS
53
Q

what are physical adaptations

A
  • external or internal
  • EXAMPLE = LOOP OF HENLE
54
Q

what is the generic name in the binomial naming system

A
  • the genus to which the organism belongs, if a species is closely related, it will share the same name
  • the first word
  • HOMO sapiens
55
Q

what is the species name in the binomial naming system

A
  • the species to which the organism belongs
  • homo SAPIENS
56
Q

why do we use a binomial naming system

A
  • to avoid confusion o common names, which are universal
57
Q

what is courtship behaviour

A
  • takes place before mating
  • carried out by organisms to attract a member of the same species
58
Q

why is courtship behaviour carried out (4 reasons)

A
  • recognise a member of its own species
  • form a pair bond
  • synchronise mating
  • become able to breed
59
Q

what is classification

A
  • the process of naming and organising organisms into groups based on characteristics
60
Q

what are the 5 kingdoms

A
  • animals
  • plants
  • fungi
  • prokaryotes
  • protists
61
Q

what is biodiversity

A
  • the variety of living organisms
62
Q

what is a species

A

a group of similar organisms able to produce fertile offspring

63
Q

what is species diveristy

A

the number of different species and the number of different individuals in a community

64
Q

what do agricultural ecosystems reduce

A
  • the biodiversity and the number of species
  • this reduces number of alleles
65
Q

how to increase biodiversity

A
  • use hedges instead of fences
  • intercropping
  • reducing use of pesticides
66
Q

how can genetic diversity within species be determined

A

compare
- frequency of observable characteristics
- base sequence of DNA
- base sequence of mRNA
- amino acid sequence

67
Q

why is comparing size and shape limited

A
  • characteristics could have been coded for by more than one gene
  • same characteristics could have arisen separately
  • characteristics influenced by own environment, not the genes
68
Q

what is used to read the base sequence of organisms

A
  • gene technology
69
Q

what can be used to eliminate sample bias

A
  • quadrat or transect

biology year 12 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions