topic 4 Flashcards

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1
Q

Non-overlapping

A

Each base is part of only one triplet.

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2
Q

Degeneracy

A

More than one codon codes for a single amino acid;

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3
Q

Codon

A
  1. Triplet / three bases on mRNA;
  2. Accept nucleotide for base
  3. That code for an amino acid;
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4
Q

Transcription

A
  1. Hydrogen bonds (between DNA bases) break;
  2. (Only) one DNA strand acts as a template;
  3. (Free) RNA nucleotides align by complementary base pairing;
  4. (In RNA) Uracil base pairs with adenine (on DNA) OR (In RNA) Uracil is used in place of thymine;
  5. RNA polymerase joins (adjacent RNA) nucleotides;
  6. (By) phosphodiester bonds (between adjacent nucleotides);
  7. Pre-mRNA is spliced (to form mRNA) OR Introns are removed (to form mRNA);
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5
Q

Translation

A
  1. (mRNA attaches) to ribosomes OR (mRNA attaches) to rough endoplasmic reticulum;
  2. (tRNA) anticodons (bind to) complementary (mRNA) codons;
  3. tRNA brings a specific amino acid;
  4. Amino acids join by peptide bonds;
  5. (Amino acids join together) with the use of ATP;
  6. tRNA released (after amino acid joined to polypeptide);
  7. The ribosome moves along the mRNA to form the polypeptide;
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6
Q

Ribosome structure

A

RNA And protein

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7
Q

Gene mutation

A
  1. Change in the base/nucleotide (sequence of chromosomes/DNA);
  2. Results in the formation of new allele;
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8
Q

Gene mutation with no effect

A
  1. Genetic code is degenerate (so amino acid sequence may not change);
    OR
    Mutation is in an intron (so amino acid sequence may not change);
  2. Does change amino acid but no effect on tertiary structure;
  3. (New allele) is recessive so does not influence phenotype
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9
Q

Gene mutation with positive effect

A
  1. Results in change in polypeptide that positively changes the properties (of the protein)
    OR
    Results in change in polypeptide that positively changes a named protein;
  2. May result in increased reproductive success
    OR
    May result in increased survival (chances);
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10
Q

Genome definition

A

(All) the DNA in a cell/organism;

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11
Q

Proteome definition

A

(The proteome is the full) range of / number of different proteins that a cell is able to produce (at a given time);
OR
(The proteome is the full) range of / number of different proteins the genome / DNA is able to code for

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12
Q

mRNA compared to tRNA

A
  1. mRNA does not have hydrogen bonds / base pairing, tRNA does;
    OR
    mRNA is linear / straight chain, tRNA is cloverleaf;
  2. mRNA does not have an amino acid binding site, tRNA does;
    Accept mRNA cannot carry an amino acid, tRNA can
  3. mRNA has more nucleotides;
  4. (Different) mRNAs have different lengths, all tRNAs are similar / same length;
  5. mRNA has codons, tRNA has an anticodon;
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13
Q

Pre-mRNA compared to mRNA

A
  1. Introns (in pre-mRNA);
  2. Removal of sections of (pre-mRNA) / splicing
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14
Q

Exon definition

A

Base/nucleotide/triplet sequence coding for polypeptide/sequence of amino acids/primary structure

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15
Q

Homologous chromosomes

A

(Two chromosomes that) carry the same genes;

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16
Q

Non-coding base sequences and location

A
  1. DNA that does not code for protein/polypeptides
    OR
    DNA that does not code for (sequences of) amino acids
    OR
    DNA that does not code for tRNA/rRNA;
  2. (Positioned) between genes
17
Q

Meiosis and genetic variation

A
  1. Homologous chromosomes pair up;
  2. Independent segregation;
  3. Maternal and paternal chromosomes are re-shuffled in any combination;
  4. Crossing over leads to exchange of parts of (non-sister) chromatids / alleles between homologous chromosomes;
  5. (Both) create new combinations of alleles;
18
Q

Causes of genetic variation

A
  1. Crossing over;
  2. Independent segregation/assortment (of homologous chromosomes);
  3. Random fusion of gametes OR Random fertilisation;
19
Q

Comparing mitosis and meiosis

A

1.   One division, two divisions in meiosis;
2.   (Daughter) cells genetically identical, daughter cells genetically different in meiosis;
3.   Two cells produced, (usually) four cells produced in meiosis;
4.   Diploid to diploid/haploid to haploid, diploid to haploid in meiosis;
Accept same number chromosomes in mitosis, but half the number in meiosis
5.   Separation of homologous chromosomes only in meiosis;
6.   Crossing over only in meiosis;
7.   Independent segregation only in meiosis;

20
Q

Substitution mutation

A

Replacement of a base by a different base (in DNA);

21
Q

Natural selection

A
  1. Characteristic due to mutation
    OR
    Allele due to mutation;
  2. Characteristic provides named advantage
  3. Individuals with characteristic more likely to survive and reproduce
    OR
    Individuals with advantageous allele more likely to survive and reproduce
  4. Directional/Stabilising selection;
  5. Frequency of allele increases (in the offspring/next generation);
    Must be applied to the context of the question
22
Q

Directional selection

A

One extreme selected/removed/favoured/chosen
OR
One extreme allowed to breed

23
Q

Stabilising selection

A

Mean selected for/chosen/favoured

24
Q

Aseptic technique

A

1.   Wash hands to remove/kill microbes
OR
Wear gloves/apron to prevent contamination;
2.   Burning Bunsen close by to create upward current of air;
3.   Disinfect bench/work on disinfected cloth to kill microbes/prevent contamination;
Accept use sterile/ antiseptic/bleach for ‘disinfect’
4.   Flame instrument/equipment to sterilise/kill microbes/prevent contamination;
Accept autoclave/ use alcohol/steam/boil for flame
Accept scalpel/ inoculating loop/wire loop/loop/forceps/ spreader for instrument
5.   Lift lid slightly to prevent entry of microbes;

25
Q

Mutations and evolutionary relationships

A
  1. Mutations change base / nucleotide (sequence);
    Reject if mutation in amino acid
  2. (Causing) change in amino acid sequence;
  3. Mutations build up over time;
  4. More mutations / more differences (in amino acid / base / nucleotide sequence / primary structure) between distantly related species;
    OR
    Few(er) mutations / differences (in amino acid / base / nucleotide sequence / primary structure) in closely related species;
  5. Distantly related species have earlier common ancestor;
    OR
    Closely related species have recent common ancestor;
26
Q

Measuring genetic diversity

A

1.   Comparing (measurable/observable) features/characteristics;
2.   Comparing amino acid sequences/primary structures (of a/named/the same protein);
3. comparing differences in the base sequence of DNA
4. Comparing differences in the base sequence of mRNA

27
Q

Importance of courtship behaviour

A
  1. Recognise / identify / attract same species;
  2. Stimulates / synchronises mating / production / release of gametes;
  3. Recognition / attraction of mate / opposite sex;
  4. Indication of (sexual) maturity / fertility / receptivity / readiness to mate;
  5. Formation of a pair bond / bond between two organisms (to have / raise young).
28
Q

Taxa

A

Kingdom, phylum, class, order, family, genus, species

29
Q

Hierarchy

A

1.Groups within groups;
2.No overlaps between groups

30
Q

Phylogeny

A

(Grouped according to) evolutionary
links/history/relationships / common ancestry

31
Q

Species

A
  1. Able to reproduce;
  2. To produce fertile offspring
32
Q

Species richness

A

(A measure of) the number of (different) species in a community;
For ‘community’ accept ‘habitat/ecosystem/one area/environment’
Reject ‘in a population’

33
Q

Index of diversity calculation

A

D = N(N-1)
En(n -1)

34
Q

Genetic diversity

A

Number of different alleles of each gene

35
Q

Farming – removal of hedges

A

More centre OR Less edge OR Less hedge OR Fewer species;

36
Q

Farming – Advantages of hedges

A

Advantage -
1.   Greater (bio)diversity so increase in predators of pests
OR
Increase in predators of pests so more yield/income/less pesticides/less damage to crops
OR
Increase in pollinators so more yield/income
OR
May attract more tourists/subsidies to their farm so more income (from diversification);

37
Q

Farming – disadvantages of hedges

A

Disadvantage -
2.   Reduced land area for crop growth/income
OR
Greater (bio)diversity so increase pest population
OR
Increase pest population so less yield/less income/(more) need for pesticides/(more) damage to crops
OR
Increased (interspecific) competition so less yield/income
OR
More difficult to farm so less income;