variation, genetics & inheritance (paper 2) Flashcards

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1
Q

variation definition

A

differences in the characteristics of individuals in a population

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2
Q

what do all variants arise from

A

mutations

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3
Q

define genetic variation

A

characters determined by the genes we inherit from parents

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4
Q

give some examples of genetic variations

A
  • eye colour
  • blood group
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5
Q

what do our genes control

A

the development of our characteristics

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6
Q

define environmental variation

A

charcateristics that can be altered or changed by lifestyle

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7
Q

give some examples of some environmental variation

A
  • tattoos
  • scars
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8
Q

what ar ethe two different categories of variation that can be represented on a graph

A
  • continuous
  • discontinuos
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9
Q

define mutation

A

a change in the DNA base sequence

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10
Q

what is the effect of a CGT nucleotide rather than CTT

A

a different amino acid is coded

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11
Q

if a protein is mutated and it is an enzyme, why might this mutation stop it from functioned

A

it can lead to a different shaped active site, which is complimentry

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12
Q

what is the name of A

A

base

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13
Q

what is the name of B

A

sugar

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14
Q

what is the name of C

A

phosphate

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15
Q

what are the names of the 4 different types of bases

A
  • C
  • T
  • A
  • G
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16
Q

which bases pair with which in a DNA structure

A
  • C pairs with G
  • A pairs with T
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17
Q

what is the name given to the structure of DNA

A

double helix

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18
Q

what is the name of this whole diagram

A

nucleotide

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19
Q

define a gene

A

a sequence of DNA that codes for a specific sequence of amino acids

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20
Q

define an allele

A

different forms (varients) of a single gene

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21
Q

define genotype

A

the combination of allelels of a single gene

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22
Q

define phenotype

A

an organisms appearance or characteristic

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23
Q

define homozygous

A

having two identical alleles for a particular gene (BB or bb)

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24
Q

define heterozygous

A

having two different alleles for a particular gene (Bb or bB)

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25
Q

in which organelle are proteins made

A

ribosomes

26
Q

how many bases code for one amino acid

A

3

27
Q

what is embryo screening

A

when the embryo is tested during the course of pregnancy to detect inherited diseases

28
Q

name a condition embryos may be screened for

A

cystic fibrosis

29
Q

what are some of the ethical issue with embryo screening

A
  • can result in abortions
  • miscarridge risk increases
  • embryo’s cannot give consent
  • parents may choose genetic makeup of child
30
Q

is DNA an example of a polermer yes or no

A

yes

31
Q

what does DNA stand for

A

deoxyribonucleic acid

32
Q

what is the genetic material inside a nucleus called

A

DNA

33
Q

what are chromosomes

A

the structures the DNA is contained

34
Q

what is a genome

A

the entire genetic material of an organism

35
Q

how many chormosomes in a human nucleus

A

46 chromosomes

36
Q

explain what is meant by ‘the gene is expressed’

A

when a gene codes for a protein that is synthsised in the cell

37
Q

describe the steps of protein synthesis

A
  • the DNA molecule is too big to leave the nucleus
  • a template is made
  • the template leaves via a nuclear pore because it is small enough
  • template goes out to a ribosome in the cytoplasm
  • carrier molecules attach to the template in order
  • when chain is complete, detaches from ribosome and folds to a specific shape
38
Q

what are proteins synthesised on

A

ribosomes

39
Q

what is the template determined by

A

the sequence of bases in the DNA molecule

40
Q

what do carrier molecules do in protein synthesis

A

bring specific amino acids to the chain

41
Q

why does the protein chain fold into a unique shape

A

it enables it to carry out its function

42
Q

define mutation

A

a change in the base sequence of a section of DNA coding for a specific trait

43
Q

what is the effect of a mutation

A
  • it may change the amino acid sequence of a protein
  • this changes its shape of the active site
  • and it may be non functional
44
Q

what does non-coding DNA do

A

switch genes on and off

45
Q

what does coding DNA do

A

code for specific proteins

46
Q

which allele is always expressed: dominant or recessive

A

dominant

47
Q

when is a dominate allele expressed

A

all the time even when only one copy is present

48
Q

when is a recessive allele expressed

A

when 2 copies of the allele is present

49
Q

what do you use to determine allele combinations for an offspring for one gene only

A

a punnett grid

50
Q

does a punnett grid determine alleles for all the genes

A

no only one

51
Q

what are the two inherited disorders we study

A
  • polydactyly
  • cyctic fibrosis
52
Q

what is polydactyly

A

having extra toes or finger

53
Q

what type of allele is polydactyly caused by

A

a dominant allele

54
Q

what is cystic fibrosis

A

a disorder of cell membranes

55
Q

what type of allele is cystis fibrosis caused by

A

two recessive alleles

56
Q

what are people called that have one recessive allele of a disease

A

a carrier

57
Q

what procedure can be carried to see if an offspring will have an inherited disorder like cystic fibrosis

A

embryo screening

58
Q

what are the female sex chromosomes

A

XX (the same)

59
Q

what are the male sex chromosomes

A

XY (different)

60
Q

what are the two methods for embryo screening (do not need to know fully just in case of reference)

A
  • aminocentisis = fluid from around feotus
  • chorionic villus spampling = sample of tissue from placenta
61
Q

what are the advantages of embryo screening

A
  • doctors can determine if the child will have an illness or disease
  • it prepares parents
  • allows parents to decide to have children or not
62
Q

what are the disadvantage of embryo screening

A
  • can result in unborn child being aborted
  • can cause miscarridge
  • expensive
  • goes against religious beliefs