genetic info, variation and relationships between organisms Flashcards

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1
Q

What are the features of the genetic code?

A

Degenerate - most amino acids code for mores than one protein
Non-overlapping - each base is only read once
Universal - the same in all living things

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2
Q

What does the order of bases determine?

A

The sequence of amino acids that form proteins

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3
Q

What is a triplet?

A

sequence of 3 bases that code for an amino acid

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4
Q

what is a gene?

A

a small section of DNA tha\t cides for a polypeptide or functional RNA

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5
Q

Describe DNA in prokaryotic cells

A

short, circular and not associated with proteins

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6
Q

Describe DNA in eukaryotic cells

A

long, linear and associated with proteins called histones

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7
Q

What is a locus?

A

a fixed position on a strand of DNA

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8
Q

What are exons and introns?

A

Exons- coding regions of a gene
Introns - non coding regions

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9
Q

What is a genome?

A

the complete set of genes in a cell

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10
Q

What is a proteome?

A

the full range of proteins that a cell is able to produce

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11
Q

What is mRNA?

A

a single strand of RNA that reads 3 bases at a time

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12
Q

What is tRNA?

A

carries amino acid to ribosomes

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13
Q

Describe the process of transcription

A

-DNA helicase breaks hydrogen bonds between 2 strands
- one DNA strand acts as a template strand
- -gree floating RNA nucleotides attach to adjacent bases
- RNA polymerase binds 2 strands together making a double helix (dettaches when reaching a stop codon)
- results in the production of mRNA
in eukaryotes it will go through splicing to remove introns

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14
Q

What is splicing?

A

The use of a spliceometer to remove any non-coding regions in mRNA (introns)

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15
Q

What is the structure of tRNA?

A

hydrogen bonding between nucleotides creates a clover- leaf shape molecule that has an amino acid binding site and an anticodon

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16
Q

Describe the process of translation

A
  • mRNA attaches to a ribosome
  • tRNA anticodon attaches to codon on mRNA
  • peptide bond forms after another tRNA is attaches
  • cycle will continue until a stop codon is reached
    -forms a polpeptide chain
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17
Q

What are gene mutations?

A

a change in the base sequence of
chromosomes

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18
Q

What are mutagenic agents + examples ?

A

factors that increase the rate of mutations e.g radiation, carcinogens, viruses

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19
Q

What is substitution?

A

when one base replaces another - doesnt cause a frame shift, not the original protein created

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20
Q

What is deletion?

A

the removal of a base causing a frame shift

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21
Q

What is addition?

A

a new base is randomly inserted into the sequence, causing a frameshift

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22
Q

What is duplication?

A

when a whole gene or section of it is duplicated , mutation isnt harmful, and it is a source for evolutionary change

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23
Q

What are advantages and disadvantages of mutations?

A

A- antibiotic resistence in bacteria, immunity to HIV, rare gene immunity protetctedx against cancer
D- can cause down syndrome, cystic fibrosis or cancers

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24
Q

What is meiosis?

A

type of cell division that results in 4 genetically different daughter cells - takes place in the gametes

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25
Q

What is crossing over?

A

when sections of sister chromatids swap geentic material resulting in genetic variation

26
Q

What is independent assortment?

A

When the side the chromatids face before being pulled apart is random resulting in genetic variation

27
Q

What does homologous mean?

A

pair of chromosomes, one from the mother and one from the father that share similar characteristics

28
Q

What is chromosome non-disjunction?

A

when chromosomes fail to separate correctly in meiosis, resulting in gametes with one more or less chromosome than normal - down’s syndrome

29
Q

Describe the process of meiosis

A
  • DNA unravels and replicates so there are two copies of each chromosome - chromatids
  • DNA condenses to form chromosomes each made from 2 sister chromatids joined by a centromere
  • Meiosis I - the chromosomes arrange themselves into homologous pairs
  • The homologous pairs are separated, halving chromosome number and creating two cells
  • Meiosis II - the pairs of sister chromatids that make up each chromosome are separated
  • Four haploid cells that are genetically different are produced
30
Q

What is genetic diversity?

A

the total number of different alleles in a population

31
Q

What is a population?

A

A group of the same species that live in the same area and interbreed

32
Q

What is a species?

A

one or more populations that can produce fertile offspring

33
Q

What factors affect genetic diversity?

A

Random mutation
Environmental factors
Selection pressures

34
Q

What is natural selection?

A

when species adapt to their environment. These adaptations may be anatomical, physiological or behavioural

35
Q

What is intraspecific competition?

A

Competition within the same species

36
Q

Describe the process of natural selection?

A
  • Random genetic mutations can create multiple alleles of genes within a population (gene pool)
  • Genetic variation within a population creates intraspecific competition
  • Individuals with particular alleles are better able to face challenges
    imposed by the environment.
  • Individuals possessing alleles which code for advantageous
    characteristics will be more likely to survive
  • Individuals that survive are more likely to reproduce and pass on the advantageous allele to the next generation
    -Therefore, over time, the frequency of the advantageous allele
    increases in the population.
37
Q

What are the 2 types of selection?

A

Stabilising - acts against the extremes and tries to reduce variation , preserves characteristics of a population
Directional - leads to a shift in mode, favouring a certain extreme , changes characteristics of a population

38
Q

Who came up with binomial classification?

A

Carl Linnaeus

39
Q

What are the 3 domains?

A

Eukaryota , Bacteria and Archaea

40
Q

What is the order of classification?

A

domain
kingdom
phylum
class
order
family
gene
species

41
Q

What is classification?

A

the arrangement of organisms into groups of various sizes on the basis of shared features

42
Q

What is taxonomy?

A

form of classification that focuses on physical similarities between
different species, for ease of naming and identification

43
Q

What is phylogeny?

A

the classification of organisms by these evolutionary relationships, so that every group shares a common ancestor
Each group is called a taxon (plural taxa)

44
Q

What is binomial nomenclature?

A

naming system used for classification -
Genus starts with capital and is underlined or in italics
Species is lower case and is underlined or in italics

45
Q

What is courtship behaviour?

A

pre-mating activities for stimulation, partner attraction and mating initiation

46
Q

What are the functions of courtship behaviour?

A

-For species recognition
-Identification of a mate that is capable of breeding
-Insures stimulation and synchronization of mating
-form a pair bond

Individuals of the same species show the
same courtship behaviours

47
Q

What is species diversity?

A

The number of different species and individuals within a community

48
Q

What is genetic diversity?

A

The variety of genes within a population of a species

49
Q

What is ecosystem diversity?

A

The whole range of different habitats on all scales

50
Q

What is species richness?

A

The number of different species in a particular area at a particular time

51
Q

What is index of diversity?

A

Total number of organisms of all species/ Sum of number of
organisms of each species

52
Q

What farming practices reduce biodiversity?

A

Removing hedgerows
Overgrazing
Creating monocultures
Use of pesticides & inorganic fertilisers
Not rotating crops/ lack of intercropping
Filling in ponds, draining wetland and marsh

53
Q

What is gene sequencing?

A

the process of determining the exact order of nucleotide bases
present in a gene, from a sample of DNA
In these computerised systems, each nucleotide base can
be tagged with a different coloured fluorescent dye

54
Q

How can genetic diversity in amino acids be measured?

A

by counting either the number of similarities or the
number of differences in each sequence

55
Q

What is DNA fingerprinting?

A

Analysing individuals DNA base sequences to see what genes or specific alleles are involved

The DNA profile will produce coloured bands and these will be compared to see the similarities and differences between them

56
Q

What is the difference between inter/intraspecific variation?

A

Interspecific- one species differs from another
Intraspecific - between members of the same species

57
Q

Why might sampling not be representative ?

A

Sampling Bias
Chance – Even if sampling bias is avoided, the individuals chosen, by pure chance, may not be representative
Sample size

58
Q

What does aseptic mean?

A

Free from contamination caused by harmful bacteria, viruses, or other microorganisms; surgically sterile or sterilized

59
Q

Describe the practical for the use of antimicrobial substances on the effect of microbial growth

A
60
Q
A