Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Genetics And The Evolution Of Life > Genetics > Flashcards

Genetics Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is the study of genetics?

A

The study of variation between and among living things

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

GENOTYPE

  • What is it dependant on?
  • What is the contribution in sexually reproducing organisms?
  • Haploid/Diploid
A
  • Entirely dependant on the parent
  • Equal contribution from the female and male
  • Haploid = One copy of each genetic unit
  • Diploid = Two copies of each genetic unit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

PHENOTYPE

  • What can it be influenced by?
  • Is it just physical appearances?
A
  • Can be influenced by both genotypes and the surrounding environment
  • Can be biochemical, such as what hormones and enzymes are being produced
  • Also the behaviour and personality, i.e. Introvert/Extrovert
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

VARIATION

- What can determine it?

A
  • Environmental Factors
  • Genetic Factors
  • Combination of Environmental and Genetic Factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

VARIATION - Environmental

  • What is it?
  • Examples
A
  • Not influenced by genes but the environment an organism lives in or the lifestyle of them. I.e. Obesity.
  • Example: Foetal Alcohol Syndrome (FAS)
  • Caused by the consumption of alcohol during pregnancy
  • Effects include: Growth retardation, Babies not growing at the same rate as others, Facial features that show signs of abnormality, CNS abnormalities, Intellectual impairment
  • Can be selective
  • Can also be influenced by: Mothers age, First or later child, What the birth was like, Planned pregnancies, Alcohol metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

VARIATION - Genetics

  • What is it?
  • Example
A
  • Mutation or change in DNA results in variation but this change will not be effected by any environmental conditions
  • Example: Huntington’s Disease
  • Mutation is unusual and a neurodegenerative disease
  • If you have the mutation, you will definitely get the disease
  • Mutation caused by a three-based repeat
  • We all have a copy of the chromosome (One from mum, one from dad)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

VARIATION - Genetics and the Environment

  • What is it?
  • Example
A
  • The most common form of variation
  • Caused by a combination of the environment and genetics
  • Example: Drosophila Wings
  • Same genotype present on the same gene locus for curly wing in two flies
  • One fly is from a hot climate, one from a cold climate
  • Effect of the temperature: The environment interacts with the gene for curly wing and effecting the way it is exhibited
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the phases of the Mitotic Cell Cycle?

A
  • G1 (Longest part of the cell cycle)
  • S (Replication of a cell’s DNA)
  • G2 (Allows cell time for additional growth and check DNA replication is complete before Mitosis)
  • M (Nuclear division occurs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the phases of Mitosis?

A

Prophase, Metaphase, Anaphase, Telophase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is Prophase in Mitosis?

A
  • Nuclear envelope breaks up
  • Chromatin slowly condenses into chromosomes
  • Spindle microtubules assemble
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is Metaphase in Mitosis?

A
  • Chromosomes line up across metaphase plate halfway between the poles
  • Each chromosome is held in tension by the kinetic horse and microtubules that attach to opposite sides of the spindle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is Anaphase in Mitosis?

A
  • Kinetochore microtubules pull two sister chromatids towards opposite poles of the spindle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Telophase in Mitosis?

A
  • Separated daughter chromosomes arrive at the poles

* New nuclear envelope forms around each daughter chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is Mitosis?

A

The process of replication of chromosomes of a single cell nucleus being distributed to two daughter nuclei. Each receive an identical, complete set of chromosomes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is meiosis?

A

Cell division that occurs in sexually reproducing organisms which the diploid chromosomes complement is halved (Haploid). Returns to diploid after fertilisation when gametes fuse. Four haploid cells are produced, each having half the chromosome number of the parent cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the phases of Meiosis?

A

Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II, Telophase II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is Prophase I?

A
  • Homologous pair of chromosomes move together an synapse - The centromeres and gene loci are matched evenly
  • During synopsis recombination, nodules appear at intervals of bivalent (Nodules = Enzyme complexes that play a role in exchange of pieces of chromatid)
  • Depending on the chromosome size, there may be more than one crossing over of bivalent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is Metaphase I?

A
  • Homologues attached at the chiasmata
  • Centromeres repel each other
  • Paternal and maternal homologues pull away from each other
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is Anaphase I?

A
  • Synaptonemal complex breaks down
  • Kinetochores of sister chromatids behave as one
  • Microtubules attach to them and assist in separation of homologues to opposite poles of the spindle
  • Homologues remain attached to chiasmata
  • Homologous pair of chromosomes separate into different cells at the later stage
  • At the end, the two new cells contain only one chromosome of each homologous pair
  • Chromosome number has been halved (Haploid); each chromosome still composed of two chromatids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is Prophase II?

A
  • Nuclear envelopes have reformed

- Chromosomes have condensed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is Metaphase II?

A
  • Nuclear envelopes have disappeared and chromosomes have lined up across the Metaphase plate with kinetochores of a chromosome facing opposite poles
  • Only one member of each homologous pair at this stage in a cell (Chromosome number has already been halved)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is Anaphase II?

A
  • Kinetochore fibres of sister chromatids point to opposite poles (Kinetochores detach from each other and sister chromatids pull apart to opposite poles and become individual chromosomes)
  • Kinetochores detach from each other and sister chromatids pull apart
  • Chromatids pull apart and become separate chromosomes
  • Each of the four chromosomes are different with respect to the combination of maternal and paternal information
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is a gene?

A
  • Fundamental unit of heredity that carries information from one generation to the next
  • Sequence of DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is DNA?

A
  • Double stranded molecule

- It is made up of many nucleotides linked together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the structure of a nucleotide?

A
  • Consists of 3 components: Deoxyribose sugar, phosphate group and a Nitrogenous base
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the bond between the sugar and phosphate group called?

A

Phosphodiester bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is a purine?

A
  • Contains 2 carbon rings
  • Adenine
  • Guanine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is a pyridimine?

A
  • Contain only 1 Carbon ring
  • Cystine
  • Guanine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Where are genes found in Eukaryotes?

A
  • Chromosomes
  • Mitochondria
  • Chloroplasts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Where are genes found in prokaryotes?

A

Plasmids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Where are chromosomes found in eukaryotes?

A

Nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Where are chromosomes found in prokaryotes?

A
  • Cytosol as they do not have a membrane bound nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is a chromosome?

A
  • Consists of DNA and protein
  • DNA is associated with a specialised protein: Nucleosome
  • Can be single stranded with one molecule of DNA
  • Can be double stranded with two molecules of DNA
  • All depends on the stage of the cell cycle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is a nucleosome made up of?

A
  • Linker DNA
  • Histones
  • H1
  • H2
  • H2B
  • H3
  • H4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is a linker DNA?

A
  • Wound around the histones H2 - H4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the histones H2 - H4?

A

DNA is wound here

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the H1 Histone?

A
  • Clamps DNA into position

- Links one nucleosome to the next

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is DNA replication?

A

Getting from double stranded to single stranded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is the first stage of DNA replication in E.Coli?

A

Helicase separates strands of DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What direction does the strand open?

A

3’ to 5’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the second stage of DNA replication in E.Coli?

A
  • DNA topoisomerase relieves supercoiling

- Single stranded proteins keep the strands apart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is the third stage of DNA replication in E.Coli? What strand can only be added to?

A

DNA polymerase III comes along and builds a double stranded sequence made from RNA (Primer)
- The 3’ strand can only be added to so it is continuously replicated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is the fourth stage of DNA replication in E.Coli?

A

Primer comes along

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is the fifth stage of DNA replication in E.Coli?

A
  • Replication occurs 5’ to 3’ on the leading strand
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the sixth stage of DNA replication in E.Coli?

A

DNA polymerase II for a new strands 5’ to 3’ on the complementary template

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is the seventh stage of DNA replication in E.Coli?

A

Primers are added to start replication and DNA polymerase II is added to the new lagging strand where Okazaki fragments are created

47
Q

What is the eighth stage of DNA replication in E.Coli?

A

Primers are removed and the gaps are filled with complementary bases while the Okazaki fragments join

48
Q

What is the ninth stage of DNA replication in E.Coli?

A

When DNA polymerase creates the leading strand on the complemntary template, beta clamps help to keep it in place

49
Q

What is DNA polymerase?

A

Digests RNA primer and replaces it with DNA

50
Q

What is DNA lipase?

A

Joins the discontinuous fragments of the lagging strand

51
Q

What is RNA primer?

A

Extended by DNA polymerase then replaced by DNA

52
Q

What is helicase?

A

Unwinds the parental double helix

53
Q

What are Okazaki fragments?

A

Short sequences formed on the lagging strand

54
Q

What is topoisomerase?

A

Relieves the tension of DNA strands

55
Q

What are single stranded proteins?

A

Hold the strand apart after helicase goes through

56
Q

What do telomeres do in DNA replication?

A
  • Protect ends of chromosomes by looping or recruit into protective proteins
  • Make sure chromosomes stay in tact
  • If lost, chromosomes get sticky ends that lead to translocation
57
Q

What is translocation?

A

When chromosomes loop back on each other or attach to other DNA because they have lost a telomere

58
Q

What is Polymerase Chain Reaction (PCR)?

A
  • Mimicking of DNA replication with an in vitro method (in the lab)
  • Only need one cell of DNA
  • Use heat to separate DNA strands (~ 90 Degrees C)
  • Can design primers so they are specific
  • Cooled down after heating to rejoin primers
59
Q

What are alleles?

A

Variants at a locus

60
Q

If an organism is homozygous AA, what gametes will it produce and in what proportions?

A

Organism will produce gametes that are all A

61
Q

If an organism is heterozygous Aa, what gametes will it produce and in what proportions?

A

Organism will create 2 types of gametes A and a in proportions of 1:1

62
Q

What is a monohybrid cross?

A

A mating of two organisms with different alleles at one genetic locus

63
Q

What offspring would be obtained between a cross of an AA male and a aa female?

A
  • AA
  • Aa
  • aa
64
Q

What would be the results for offspring with male pool gametes of A, A, a, a and female pool gametes of A, A, a, a?

A

F2 = AA, Aa, Aa, aa

A second generation cross between parents will produce 3 genotype in proportions 1:1:1

65
Q

What is a back cross?

A

A cross of offspring to a parent

66
Q

What is independent assortment?

A

When more than one pair of chromosomes is followed through a meiotic division

67
Q

What is a Di hybrid cross?

A

Involves two gene loci

I.e: AA;BB x aa;bb

68
Q

What is linkage?

A
  • Several genes existing on a chromosome

- Independent assortment of genes may not occur

69
Q

What is the cis arrangement?

A

AABB are on one chromosome while aabb are on the other chromosome. They are all the same.

70
Q

What is the trans arrangement?

A

AAbb are on one chromosome while aaBB are on the other chromosome. They are not the same.

71
Q

What is the frequency of recombination?

A

Measures the relative distance between gene loci

- 1% recombination = 1 map unit

72
Q

How do you work out map distance?

A

(Number of recombinant offspring/Total offspring) x 100

73
Q

How do you test for linkage?

A

Performs a test cross of a heterozygote to a homozygous recessive
I.e: Aa x aa OR Aa;Bb x aa;bb

74
Q

How do we know if two loci are asserting independently?

A

A test cross of a heterozygote will produce 4 genotypes in a phenotypic ratio of 1:1:1:1

75
Q

What is incomplete dominance?

A

No trait is dominant

  • Genotypic ratio of 1:2:1
  • Phenotypic ratio of 1:2:1
76
Q

What is an example of incomplete dominance?

A

Pink flowers formed from red + white flowers.

  • They form from having half the amount of red
  • Will be heterozygous
77
Q

What is codominance?

A

See the expression of the heterozygote in the alleles

- Monohybrid ratio with codominance = 1:2:1 for phenotype

78
Q

What is an example of codominance?

A

Sickle Cell Anaemia

79
Q

What is Sickle Cell Anaemia?

A
  • Mutation of alleles effects production of beta-globin
  • Mutation effects the RBC by distorting them as they pass through capillaries, blocking them and causing heart failure, etc.
  • Heterozygote has both alleles
  • HBA will produce normal RBC
80
Q

What did Beadle and Tatum do with Neurospora Crassa?

A

Discovered that arginine was a key amino acid required by fungus to grow

81
Q

What does a gene do?

A
  • Can code for an enzyme and ultimately a polypeptide
82
Q

What do genes also code for?

A

RNA

83
Q

What are the extensions to Mendel?

A
  • Multiple Alleles
  • Phenocopy
  • Pleiotropy
  • Variable Expression
  • reduced Penetrance
  • Lethality
84
Q

What are multiple alleles?

A
  • When you have more than two alternatives at a locus

- Increases variation

85
Q

What is are three examples of multiple alleles?

A
  • Tabbying in cats
  • Clover chevron markings
  • Human gene
86
Q

What is a phenocopy?

A
  • The copy of an inherited condition but results from an environmental factor
  • Environment modifies the phenotype to mimic the effect of a specific genotype
  • NOT INHERITED
87
Q

What is an example of Phenocopy?

A

Meromelia

88
Q

What is Pleiotropy?

A

When a single gene may affect many features of the phenotype

89
Q

What are three examples of pleiotropy?

A
  • Sickle Cell Anaemia
  • Albinism
  • Pure white cats
90
Q

What is variable Expression?

A

The degree or range in which a particular phenotype is expressed by individuals

91
Q

What is an example of variable expression?

A

Polydactyly

92
Q

What is reduced penetrance?

A
  • Proportion of genotypes that show the expected phenotype
  • Anything under 100% is said to have reduced penetrance
  • Penetrance may be influenced by environment (E.g. Temperature)
93
Q

What are two example of reduced penetrance?

A
  • Polydactyly

- Siamese cats

94
Q

What is lethality?

A

A genotype, allele or mutation that results in death

95
Q

What is a recessive lethal?

A

Kills when a genotype is homozygous (aa, AA) whether the phenotype is dominant or recessive

96
Q

What is a dominant lethal?

A

Kills when a genotype is homozygous dominant or heterozygous

97
Q

What are two examples of lethality?

A
  • Yellow mice

- Achondroplasia in humans

98
Q

What are the five sex determining mechanisms?

A
  • Environment
  • Genes
  • Haplo/Diploidy
  • Balance of autosomes to sex chromosomes
  • Sex chromosome
99
Q

What effect does environment have on the sex of an organism?

A
  • Sex is not determined at conception when the gametes come together
100
Q

What are two examples of the environmental effect of sex determination?

A
  • Sea worm gamete location

- Incubation of reptile eggs

101
Q

What effect do genes have on the sex of an organism?

A

A particular genotype may change the expected sexual phenotype

102
Q

What are two examples of the effect of genes on sex determination?

A
  • Drosophila tra gene

- Human androgen insensitivity

103
Q

What is Haploidy/Diploidy?

A

Associated with the organism being haploid or diploid

104
Q

What is an example of Haploidy/Diploidy?

A
  • Honey bees
105
Q

What is the effect of autosomes/sex chromosomes on the sex of an organism?

A

The sex is determined by the ratio of chromosomes:autosomes

106
Q

What is an example of autosomes/sex chromosomes effecting the sex of an organism?

A

Drosophila

107
Q

What effect do sex chromosomes have on the sex of an organism?

A

For humans, the presence of the Y will determine the sex

108
Q

What are two examples of sex chromosomes determination sex?

A
  • Non-disjunction in the female

- Non-disjunction in the male and fertilisation

109
Q

What is the Sex Determining Region of Y (SRY) locus?

A

SRY encodes a testes determining factor to differentiate the organisms gametes. When presence, organism will be male

110
Q

What are heterogametic males?

A

The gametes in the male are different, XY for example, and produces two types of gametes in respect to chromosomes (Y-Baring and X-Baring). XO can also occur, producing gametes with with an X or without an X. The female will be homogametic

111
Q

What are four examples of the male being heterogametic?

A
  • Humans
  • Drosophila
  • Locusts
  • Grasshoppers
112
Q

What is a female heterogametic?

A

The gametes in the female are different, ZW for example, and produces two types of gametes in respect to chromosomes (Z-Baring and W-Baring). The female will be homogametic

113
Q

What are four examples of the female being heterogametic?

A
  • Birds
  • Fish
  • Butterflies
  • Moths

Genetics And The Evolution Of Life (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions