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Human Biology > chapter 12-15 > Flashcards

chapter 12-15 Flashcards

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1
Q

Define species

A

group of individuals that share many characteristics and are able to interbreed to produce fertile offspring

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2
Q

Define population

A

group of organisms of the same species that some together in a particular place at a particular time

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3
Q

Define allele frequencies

A

how often a articular allele occurs in a gene pool - may change due to events (mutations) or environmental

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4
Q

Define allele

A

alternate form of a gene

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5
Q

Example of allele frequency

A

Cystic fibrosis allele is found in chromosome 7
Frequency - 5%
for every 100 people, 5 carry the cystic fibrosis allele chromosome 7

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6
Q

Types (categories) of mutations

A

chromosomal/genetic (during cell division) & somatic/germinal (body and sex cells)

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7
Q

Define mutation

A

accidental/by chance change in the chromosome or genes which arise characteristics unseen in parents
- may have advantages/disadvantages

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8
Q

Define a mutagen + examples

A

agents known to increase he rate at which mutations occur

examples - uv radiation, sulfur dioxide, antibiotics, mustard gas, x-rays

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9
Q

Dangers of x-rays in pregnancy

A

may cause retardation, skeletal malformations, small head

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10
Q

Describe somatic mutation

A
  • body and muscle cells
  • may arise and be replicated to other cells, but not passed to offspring
  • doesn’t affect reproductive cells - not generational - destroyed at death
    cancerous cells may be involved
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11
Q

Describe germinal mutation

A
  • gametes
  • may be inherited
  • mutant usually isn’t affected
  • if mutation has occurred and is dangerous, baby is often naturally aborted
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12
Q

What is Phenylketonuria (+symptoms)

A
  • recessive
  • germinal/genetic mutation
  • A birth defect that causes an amino acid called phenylalanine to build up in the body.
  • error of metabolism - results in decreased metabolism of the amino acid phenylalanine
    SYMPTOMS
  • short stature, physical/intellectually slow.
  • Untreated phenylketonuria can lead to brain damage, intellectual disabilities, behavioural symptoms or seizures.
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13
Q

Describe genetic mutations

A
  • occurs in base pairs
  • DNA - double helix with corresponding sugar-phosphate nucleotide bases
  • point mutation - change in one base pair
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14
Q

What is a point mutation (eg)

A
  • change in one base pair
  • may have no effect, change the protein formed or stop production all together
  • example - sickle cell anaemia
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15
Q

List 6 GENETIC disorders

A
  • Albinism
  • Duchenne (for of muscular dystrophy)
  • Cystic fibrosis
  • Tay-sachs disease (TSD)
  • Sickle cell anaemia
  • Thalassaemia
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16
Q

Describe albinism

A
  • inherited, recessive
  • absence of pigment from skin, hair and eyes - often white skin/hair, pink eyes
    missing protein = genetic, germinal mutation
  • congenital disorder (physical and from birth)
  • astigmatism, blurred vision, or sensitivity to light
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17
Q

Describe Duchenne (muscular) dystrophy

A
  • MALES
  • genetic/germinal
  • inherited/recessive
  • mutation occurs within mother - passed to sons
  • Mutation may also develop in a male zygote
    Progressive degeneration - weakness of leg then arm muscles
  • Eventually die from collapse of respiratory muscles
  • Lives to around 20-25 years
  • absence of dystrophin, a protein that helps keep muscle cells intact.
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18
Q

Describe Cystic Fibrosis (type of mutation/ what is it/ symptoms /treatment)

A
  • genetic, germinal
  • Recessive
  • point mutation
  • Chromosome 7
  • Mutation occurs in a gene that codes for amino acids that regulate the passage of chloride ions across the cell membrane
  • Cystic fibrosis affects the cells that produce mucus (mucous glands), sweat and digestive juices. It causes these fluids to become thick and sticky. They then plug up tubes, ducts and passageways.
  • traps harmful bacterias and therefore they more susceptible to infection - irreversible lung damage
  • Symptoms vary and can include cough, repeated lung infections, inability to gain weight and fatty stools, Salty skin, coughing, wheezing
  • Treatments - gene therapy - may ease symptoms and reduce complications.
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19
Q

Describe Tay-Sachs disease (TSD) (where found)

A
  • autosomal
  • recessive
  • mental and physical disabilities
  • disorder of lips metabolism - fatty substances build up in the nervous system
  • normal at birth then degeneration - death
  • believed resistance to tuberculosis
  • eastern europe - jews
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20
Q

5 types of chromosomal mutations

A
  • deletion
  • duplication
  • inversion
  • translocation
  • non-disjunction
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21
Q

Deletion mutation:

A
  • chromosomal

- part of the chromosomal is lost

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22
Q

Duplication mutation:

A
  • chromosomal
  • section of the chromosome occurs twice
  • part of a chromosome breaks off and joins another random chromatid
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23
Q

Inversion mutation:

A
  • chromosomal
    part of chromosome is broken
  • joins back-to-front
  • may effect order of genes and homologues pairs during meiosis
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24
Q

2 types of genetic cells mutated

A

germinal & somatic

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25
Q

3 types of genetic mutations (and brief meaning)

A
  • point mutations (mutation in one base)
  • deletion (one or more base pairs are lost from the DNA)
  • insertion (insertion of additional base pairs that may lead to frame shifts)
  • can be detected by DNA sequencing
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26
Q

Translocation mutation:

A
  • part of chromosome falls off and joins another
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27
Q

Non-disjunction mutation:

A
  • chromosome pairs are not separated properly

- extra chromosome

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28
Q

List 5 chromosomal disorders

A
  • Down syndrome
  • Patau syndrome
  • Kleinfelter syndrome
  • Cri-du-chat syndrome
  • Turners syndrome
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29
Q

Describe Down syndrome (type of mutation

A
  • trisomy (extra chromosome on 21 - now 47)
  • non-disjunction
  • failure of separation of chromosomes during second stage meiosis
  • causes a distinct facial appearance, intellectual disability and developmental delays.
  • It may be associated with thyroid or heart disease.
  • Usually die younger than average - heart failure
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30
Q

Patau syndrome

A
  • trisomy (extra chromosme) - may be XXY / XYY
  • non-disjunction
  • extra fingers, small head, cleft plat/lip deformed, deformed ears and eyes
  • mental retardation
  • comes from mother
  • usually miscarriage / early birth
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31
Q

Kleinfelter syndrome

A
  • chromosomal
  • trisomy
  • non-disjunction
  • recessive/
  • (XXY) XYY - boy with deformities
  • small testes, large chest/breasts, lack of body hair, sometimes mentally retadred
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32
Q

Cri-du-chat syndrome

A
  • chromosomal
  • monosomy (missing chromosome)
  • autosomal
  • part of chromosome 5 is missing
  • severe deformaties - larynx and nervous system
  • cry like a cat as a baby
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33
Q

Turners Syndrome

A
  • chromosomal
  • Monosomy
  • women
  • short stature, lack secondary sex characteristics, wide neck
  • diagnosed before birth from abiotic fluid
34
Q

Define/describe biotechnology

A

use cellular processes make products that are of use use to human beings

  • hormones, antibiotics
  • genetic testing, gene manipulation, cell replacement therapies and tissue engineering
  • identify location of disorders
35
Q

Define genome

A

complete set of genetic information of an organism - complete setoff nucleotides

36
Q

DNA description (what, where, structure, components)

A
  • deoxyribonucleic acid - deoxynucleotide triphosphate
  • double helix strand of alternating sugar (deoxyribose) + phosphate groups
  • found in nucleus and mitochondria (aerobic phase)
  • 5 carbon sugar
  • four nitrogenous bases - A, T, C, G
  • 5’ prime (point of sugar) and 3’ prime (opposite end)
  • weak hydrogen bonds
37
Q

DNA sequencing define

A

determination of the precise order of nucleotides in a sample of DNA

38
Q

DNA sequencing method/process

A
  • synthetic nucleotides are added to growing strand - they lack (OH) bond group so stops joining
39
Q

DNA sequencing uses (E.G)

A
  • used DNA sequencing to identify location of mutation
  • show whether a person will develop an inherited disease - comparing DNA can show changing alleles
  • Point mutations, insertions, deletions are identified
    E.G - spastic paraplegia - regressive limb weakness - paralysis - 20-30 year olds - no cure
  • Sickle cell anaemia, cystic fibrosis, cancers can be determined
  • Also used for paternity/maternity tests - see who’s the father
40
Q

Description on gel electrophoresis (what/uses)

A
  • DNA fingerprint
  • restriction enzyme from bacteria used to cut DNA into small lengths
  • smaller fragments move to positive end - opposite charges attract
  • Used for identification of hereditary diseases, ancestry, identification (criminal/family)
41
Q

Description on gel electrophoresis (what/uses)

A
  • DNA fingerprint
  • restriction enzyme from bacteria used to cut DNA into small lengths
  • smaller fragments move to positive end - opposite charges attract
  • Used for identification of hereditary diseases, ancestry, identification (criminal/family)
42
Q

Polymerase chain reaction (define/uses)

A

segments of DNA are copied, alined through multiple cycles of replication

  • used when test DNA/subjects are low in numbers - for electrophoresis eg
  • identification of hereditary diseases - cystic fibrosis, Phenylketonuria, sickle cell
43
Q

Recombinant DNA technology define/what is it

A

introducing modified or enhanced DNA into a cell from another organism (bacteria/yeast)

44
Q

Uses for recombinant DNA technology + eg (what’s bacteriophage)

A
  • treatment of disease - Used to replace genes (if faulty eg) - cystic fibrosis, rheumatoid arthritis, cancers
  • diagnosis - detects if someone is carrying hereditary disease - inserting antibiotics
  • genetically engineering proteins/hormones (Manufacturing proteins - FSH, insulin, growth hormone, factor VIII (8))
45
Q

Steps (4 main) of recombinant DNA technology

A
  1. Isolate the gene and cut out desired DNA segment using restriction enzyme - cut fragment on either side that contains desired segment - may have clean cut (blunt end) or sticky end
  2. Remove/prepare plasmid - plasmid (vector) from bacterial cell that you want to edit, using same type of restriction enzyme that cut the DNA segment - will now have sticky end or clean cut
    • plasmids (cytoplasmic DNA) can replicate independently within the cytoplasm
  3. During ligation, DNA ligase connects/places the gene of interest into the plasmid, joining the sticky end creating a “complete circle”
  4. Insert recombinant DNA into treated bacterium (agar) to be duplicated/cloned and programmed to create the protein that the gene coded for (insulin e.g)
    • something to do with antibiotic
46
Q

Use of insulin in recombinant D.T

A
  • people with type 1 diabetes have elevated blood sugar levels due to the impaired insulin production in the beta cells of the islets of langerhans in the pancreas
    Insulin regulates the use and storage of glucose
  • Was produced by genetically engineered bacteria - now use mostly yeast cells
    Gene that codes for insulin in humans has been introduced into bacterial cells so that it may grow and produce insulin
    Genetically engineered insulin treats diabetes - no side effects
  • genetically engineered by E. coli
47
Q

Creation and use of insulin in recombinant D.T

A
  • people with type 1 diabetes have elevated blood sugar levels due to the impaired insulin production in the beta cells of the islets of langerhans in the pancreas
    Insulin regulates the use and storage of glucose
  • Was produced by genetically engineered bacteria - now use mostly yeast cells
  • Gene that codes for insulin in humans have been introduced into bacterial cells so that it may grow and produce insulin
    Genetically engineered insulin treats diabetes - no side effects
  • genetically engineered by E. coli
48
Q

Creation and use of Human growth hormone in R.D.T

A
  • genetically engineered by E. coli
  • Genetically engineered used to try improve/enhance athletic performance, delay physical deterioration (ageing) - little evidence and there is side effects
  • Used in animals - cows - increased milk production - no harm to humans
49
Q

Creation (before and now) and use of Factor VIII in R.D.T

A
  • Haemophilia A - inherited disorder - blood clotting protein (factor 8) is deficient
  • # Can’t adequately clot - can’t form scabs and stop bleeding - can die from blood lossBEFORE - many donors are required - means that high risk of spread of infection/disease - hepatitis C and human immunodeficiency virus (HIV) are most common
    NOW - created by recombinant DNA so less infections spread
    Cultured in mammalian cells
    Treatment - injections of factor 8 concentrates made from human plasma
50
Q

Describe cell replacement therapy / tissue engineering (what/uses/components used)

A
  • Stem cells - undifferentiated cells that can differentiate into specialised cells
  • Replacement therapy - used when someone has lost or injured normal cells
  • Neurodegenerative disorders have most interest - Parkinson’s and alzheimers eg
  • Replacement of dying neurons in the brain
  • Embryo stem cells used although raises ethical questions
  • Tissue engineering - restore tissue from recipients instead of transplant
  • Scaffolds - requires specific disease-free cells to grow on a scaffold of natural or synthetic material to produce a 3D tissue - tissue can then grow from it
  • Eg are bone, cartilage, skin, tissues, adipose tissue (body/muscle)
51
Q

Huntington’s disease (type of mutation/where/what/symptoms/treatment)

A
  • point mutation
  • genetic
  • chromosome 4
  • brain damage (nerve) - mutation of protein called Huntington - results in damage of nerve in the brain
  • unintentional movement of limbs
  • progressive dementia
  • unclear thoughts
  • gene therapy treatment
52
Q

List 5 processes that create variation

A
  • crossing over
  • random assortment
  • random fertilisation
    mutation
  • non-disjunction
53
Q

What is random assortment (variation)?

A

when gametes fuse, maternal and paternal chromosomes may align on either side (in homologous pairs) - not all chromosomes of same parent will end in the same cell

54
Q

What’s crossing over (variation)?

A
  • crossing over within homologous pairs = mixture of genes from mum and dad - during meiosis may result in pieces being broken / misplaced / moved to wrong section = disorders
55
Q

What is non-disjunction (variation)

A

when one or more chromosome pairs fail to separate leaving one extra/less chromosome

56
Q

What is random fertilisation (variation)

A

Random fertilisation - people produce millions of gametes that are all different - endless combinations of unique sperm and egg cells

57
Q

What is a mutation (variation)

A
  • permanent changes in DNA of a gene or of a chromosome that result in changed / new / different characteristics in someone - can be inherited - introduces new alleles into the gene pool
  • happen by chance
58
Q

Define natural selection (Eg)

A
  • Nature favours a characteristic/set of alleles at the expense of another
  • Favourable allele that usually enhance survival reproduction of species
  • e.g if big feet = survival, then more people with big feet would survive at the expense of the loss of smaller foot people - therefore allele frequency would decline or increase
59
Q

Discuss random genetic drift (what/what types of people/communities/ eg)

A
  • Sewall Wright effect
  • Usually occurs in smaller isolated communities - random non-directional variation
  • Little-to-no input of new alleles (from other countries/cultures/states/areas)
  • Means that two closely related populations could be very different if isolated over long time
  • Rare alleles may become popular/die out in smaller populations by accident
  • eg. Certain hair colours/types, blood groups, hand dominancy, may be similar in small group
60
Q

Discuss Founder effect (what/who’s involved/eg)

A
  • part of a population moves away to an isolated area and are not representative of their homeland people
  • then see “new” populations form, different from home
    eg. Achromatopsia - colourblindness
61
Q

Discuss Migration (what/who’s involved/eg)

A
  • gene flow from one population to another
  • immigrants from other countries bring in new alleles
    e. g rhesus factor - antigen found on surface of red blood cells - = Chinese all had (+) then europeans brought in (-)
62
Q

List 3 barriers to gene flow (eg for each)

A
  1. geographical barriers (oceans/mountains/river)
  2. social barriers (religion/economical/educational)
  3. language barriers (people often breed with people of their own language and with their own culture)
63
Q

Thalassaemia (what/where/symptoms/treatment)

A
  • genetic mutation
  • form of anaemia (less than normal oxygen circulation)
  • mediterranean decent (cousin marriages were common)
  • defects in the formation of haemoglobin
  • fatigue, weakness, slow growth
  • blood transfusions
64
Q

Sickle cell anaemia (what/where/why/symptoms/treatment)

A
  • point mutation
  • genetic disorder
  • recessive
  • Sickle shape stick together and causing blockage of arteries/veins - insufficient oxygen supply to organs and cells
  • Heterozygous provides degree of immunity to malaria
  • Natural selection/survival of the fittest kept it in - homozygous died and homoz. Normal got malaria (widespread in African areas)
65
Q

Define evolution (eg research)

A

Gradual change in characteristics of a species over time - Galapagos islands

66
Q

Define ‘birth rate’ in theory of natural selection

A

reproduction occurs at a greater rate than their food sources increase - stops overcrowding

67
Q

Define survival of the fittest

A

organisms with greatest, most suited/desirable characteristics survived while the rest died before reproduction

68
Q

List 3 examples of natural selection in humans

A
  • body stature
  • sickle cell anaemia
  • speciation
69
Q

Describe ‘body stature’ as example of natural selection

A
  • people with long body but small limbs (smaller surface area in relation to body volume) lose less body heat - survive better in colder conditions
  • People with shorter bodies and longer limbs have greater surface area - lose more heat - better in hotter conditions
    Favourable alleles so stays in gene pool
70
Q

Describe ‘sickle cell anaemia’ as example of natural selection

A
  • Arose during the cultivation of crops which provide perfect breeding environment for anopheles mosquitos
  • heterozygous people for sickle cell allele were less susceptible to infection from malaria compared to normal people and homozygous
  • having one of the alleles in this malaria-prone areas acted as an advantage for survival
  • two alleles would of course die
  • With this, heterozygous sickle-cell people became more populated due to natural selection
  • They passed on the singular allele to their offspring unless unfortunately their child received two and died
71
Q

4 stages of speciation

A
  1. variation - must be existent variation within population
  2. isolation - barrier formed - can’t interbreed between split groups
  3. selection - selection pressure force change in frequencies of genes
  4. then become so different that they can’t breed between and are now different species
72
Q

List 6 types of evidence for evolution

A
  • DNA
  • Mitochondrial DNA
  • Protein sequences
  • Embryology
  • Homologous structures
  • Vestigial organs
73
Q

Describe DNA as evidence for evolution (eg)

A
  • non-coding/junk DNA (no purpose)
  • can compare this DNA between like species to see similarities
    eg. - Endogenous retroviral DNA - viral sequence that stores genetic info as RNA - turning it to DNA when enters cell - reverse transcription
  • inherited if effects zygote
74
Q

Describe Mitochondrial DNA (what/where/appearance /structure/codes)

A
  • Organelles in the cell where aerobic respiration occurs to release energy for cell use
  • Most DNA is in nucleus but some in mitochondria as mtDNA
  • Small circular form
  • 5-10 molecules in each mitochondrion
  • Total of 37 genes - 24 code for tRNA for protein synthesis
  • Other 13 for enzymes for cellular respiration
  • Mutations can cause disease
  • Cells contain large amount - easy to extract
75
Q

Mitochondiral DNA as evidence for evolution

A
  • eggs/ovum have hundreds of mtDNA, sperm only have few - enough for travel
  • When sperm penetrates the ovum, mtDNA is destroyed
  • Nuclear DNA comes from both parents and mtDNA only from mothers
  • Most mutations occur in mtDNA - why this DNA has diverged from ancestors
  • Similarities in mtDNA between shows estimate of closeness of their relationship through maternal mothers - very different shows that common ancestors lived long ago
  • Traces migration routs
  • Maps relationships between species
76
Q

Protein sequences has evidence for evolution (eg)

A
  • proteins come form the food we eat
  • organisms within a species share very similar protein sequences
  • Linking together amino acids in a precise sequence determined by the DNA creates these proteins
  • Comparing similar protein sequences between species - similarity and differences can be established - for evolution evidence
  • 20 kinds of proteins
  • Degree of difference determines connection and time

eg. - Cytochrome C - protein performs essential step in cell. respiration
- Been found in same position in many species
- When compared between species - more similarities = closer

77
Q

Describe bioinformatics (use)

A
  • use of computers to describe the molecular components of living things
  • Assist evolutionary biologists in tracing evolution of organisms in large numbers
  • Measures changes
  • By hand takes too long
  • Annotation - biological features in a DNA sequence need to be identified
78
Q

Describe embryology as evidence for evolution

A
  • Compares the early stages in the development of organisms
  • Hard to distinguish as embryos - similar
  • Structures show that they perhaps started out the same then differentiated into their own kind
  • Evidence for common ancestry - similar tail, vertebrae, 2 chamber hearts, brain development, appendages
79
Q

Describe homologous structures as evidence for evolution

A
  • Similarity in forelimbs of vertebrae
  • Homologous organs - bones are arranged in similar way but developed different functions - lIkely to have common ancestors
  • Full skeletons are similar to
  • Similar muscles
80
Q

Vestigial Organs

A 
- structures of reduced size that have no function
Nictitating membrane - Pink membrane / third transparent eye lid - found on birds, dogs…
Wisdom teeth - usually removed 
Coccyx  
Appendix
Hair on body
Nipples on men
Ear muscles
Segmented muscles on abdomen 
Pyramidalis muscle - above pubic bone
81
Q

List 4 causes of changes in allele frequency

A
  • mutations
  • differing selection pressures
  • random genetic drift, including the founder effect
  • changes in gene flow between adjoining groups

Human Biology (2 decks)

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