Genetics Flashcards

1
Q

two ways of reproducing

A

asexually and sexually

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2
Q

traits of asexual repoduction

A
  • division is by mitosis
  • onne parent
  • no genetic variation- all are identical
  • divides once to make two cells
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3
Q

where is asexual rerproduction common

A
  • small organisms like fungi, small plants and bacteria
  • large plants like daffodils
    -body cells
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4
Q

traits of sexual reproduction

A
  • involvlves 2 parent sex cells- gametes- fusig together to form a zygote
  • offspring will have variation
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5
Q

what are gametes and how are they formed

A
  • gamete are sex cells
  • formed by meiosis
  • examples are sperm and egg cells
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6
Q

what does meiosis form

A

sex cells

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7
Q

where does meiosis take place

A

reproductive organs
- eg ovaries and testes

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8
Q

what happens in meiosis

A
  1. all chromasomes in the cell are copied/doubled so there are four of each chromasome
  2. the cell dviides in two
  3. cell dviides a secod time to make four gametes- all of these cells will have one set of chroasomes rather than pairs
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9
Q

what happens at fertilisation

A
  • two gametes join together
  • both have 23 chromasome rather than 46 so join to make 23 pairs
  • the combination of genes in the chromasomes is uique
  • the new cell then begins to divide by mitosis to form an embryo
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10
Q

what are chromasomes made up of

A

long molecules of DNA

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11
Q

what are genes

A

small sections of dna
- this is where genetic info is stored

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12
Q

what is DNA

A
  • inside chromasomes
  • long two strands of polymer molecules that twist
  • forms a double helix structure
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13
Q

what do genes do

A
  • stores genetic info
  • each gene codes for a particular sequence of amino acids to make a specific protien
  • these protiens control the make of enzymes and specialised cells and tissues which form organs
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14
Q

whats a genome

A

the entire genetic material of an organism

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15
Q

explain the mitochondria and dna

A
  • the mitochondria has its own DNA
  • you inherit it always from your mother
  • it comes from the egg
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16
Q

what can understandig the human genome do

A
  • helps uderstand iherited disorders eg cystic fybrosis
  • undertsand ad identify genes that cause certain diseases
  • helps choose optimal treatment
  • trace human migration patterns through similarities in dna
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17
Q

what are alleles

A

different variants of genes you inherit

18
Q

homozygote

A

someone with two of the same alleles for a characteristic
eg BB/ two blue eye genes

19
Q

heterozygote

A

someoe with dif alleles for a charcateristic
eg. Bb two dif eye colours

20
Q

genotype

A

genetic makeup of a person in a particular characteristic/ the alleles they have in a gene
- eg Bb or bb

21
Q

phenotype

A

the phsyical appearance of an individual regarding a characteristic
eg. someone visably has blue eyes

22
Q

whats a dominent allele

A

an allele that will always be expressed in the phenotype when present

23
Q

whats a recessive allele

A

can only be expressed on the penotype/ control the protiens made if it is the only allele present

24
Q

whats a genetic cross

A

considering the offspring from two parent cells
- often modelled using a punnet square

25
Q

what does a punnet square show

A
  • alleles carried by each parent
  • all possible gametes to be formed by these
  • how these may combine to form gentotypes and phenotypes
26
Q

female sex chromasomes

A

XX

27
Q

male sex chromasomes

A

XY

28
Q

WHAT IS POLYDACTYLY

A
  • extra fingers and toes
  • caused by a dominent allele from a parent
29
Q

what is cystic fibrosis

A

-affects organs such as lungs, digestion and reproduction
- cell membranes dont allow substances to pass resultung in thick mucus build up particually in the lungs and in the area where the pancrease would release enzymes
- infertility

30
Q

is cystic fibrosis recessive

A
  • yes it comes from a recessive allele
  • ## if two w the allele have a child theres a 25% chance the child has it but a 75% chance they would carry
31
Q

how to treat cystic fibrosis

A
  • antibiotics to clear lungs of mucus
  • enzymes to replace the ones that cant be secreted by the pancreas
32
Q

what does genetic screening do

A

helps people see whether they carry a faulty allele
can help see if foetuses carry an inherited disorder
can be screened during ivf before implantation

33
Q

ways to screen a foetus

A
  • amniocentesis
  • chorioic villus sampling
  • screen during ivf before foetus is implanted
34
Q

process of amniocentesis

A
  • around 15 weeks of pregnacy
  • takes fluid from fetus
  • screens fetal cells in the fluid
35
Q

process of chorioic villus sampling

A
  • earlier than amniocentesis at 10 weeks
  • takes small sample of tissue
  • provides fetal cells
36
Q

concerns of genetic screening

A
  • increases risk of miscarriage
  • can give false positives or egatives
  • difficult descision if to terminate a pregnancy, can be distressing
  • expnsive
  • concerns it increases a need for ‘designer babies’ and the abolition of disabilities/appearance/geder
  • no way to cure the disorder
37
Q

which cells fuse in sexual reproduction in plants

A

pollen and egg

38
Q

what is bacterias reproductive process called

A

binary fission

39
Q

what is haploid

A

a cell has half the normal genetic material eg a gamete

40
Q

positive aspects of embryo/genetic screening

A
  • reduces suffering of children
  • saves people money of treating inherited disorders
41
Q

what is IVF

A

fertiliisng and growing an egg in a lab before reincerting into the womb