Module 2 Flashcards

1
Q

Nondisjunction?

A

Failure of chromosomes to separate properly during meiosis.

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

Aneuploidy?

A

Abnormal number of a particular chromosome

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

Deletion?

A

removal of a chromosomal segment

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

Inversion?

A

Reverses a segment within a chromosome

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

Duplication>

A

Repeated segment within a chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Translocation?

A

Removal of a segment from one chromosome to a non-homologous chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Polyploidy?

A

possession of multiples sets of chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Disease resulting from nondisjunction?

A

Down Syndrome, 95% of DS babies have 2 maternal chromosome 21

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Diseases resulting from Aneuploidy?

A

Klinefelter syndrome (XXY) and Turner Syndrom (XO)

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

Disease resulting from Deletion?

A

Lejeune Syndrome, tip or short arm of chromosome are deleted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Diseases resulting from translocation?

A

Myeloid Leukemia, TK overexpression, Familial Down Syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do chromosome abnormalities and rearrangements occur.

A

Mutations & Nondisjunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Explain the effects of odd numbers of chromosomes in meiotic segregation?

A

An odd number of chromosomes will mean the organism is sterile/infertile as they can not produce viable gametes

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

Outline the concept of X-inactivation?

A

X-inactivation occurs in females because they have two copies of the X chromosome, one from each parent. One X chromosome is compacted into a structure calle Barr Body which contains mostly inactive genes. Whether it is the paternal or maternal X chromosome varies randomly from cell to cell. This process happens during embryonic development and is also referred to a lysonization.

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

What are the birth defects of chromosome abnormalities and rearrangements.?

A

EMbryo will often die early or have physical abnormalities and a decreased life expectancy

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

What is gene expression>

A

The process by which information from a gene is used to synthesis a functional gene product: Protein or non-coding RNA

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

Define a gene?

A

A define region of DNA that produces a type of RNA that has some function.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are gene (DNA) sequences responsible for?

A

Regulation of the synthesis of RNA
producing RNA
Future processing of RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the central Dogma of molecular biology?

A

The process by which DNA is converted to RNA to protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Transcription?

A

The synthesis of RNA using a DNA template (MRNA is transcribed from the template strand)

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

Which DNA strand is transcribed?

A

Template strand = strand running in the 3-5 prime direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What occurs during Initiation?

A

Transcription factors bind to TATA box and other regions of the promotor,
RN pol II binds, forming a transcriptional initiation complex together with the transcription factors,
The two DNA strands seperate and RNA pol II starts mRNA synthesis without the need of a primer.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What occurs during Elongation?

A

RNA pol II uses the template strand as a template and inserts complementary RNA nucleotides in the 5-3 direction.

24
Q

Where does Transcription. occur?

A

In the Nucleus

25
Q

Where does Translocation occur?

A

In the cytoplasm

26
Q

What is a coding sequence?

A

Portion of a genes DNA that is translated into a protein

27
Q

What is the proimotor?

A

DNA segment recognised by RNA polymerase to initiate transcription

28
Q

What is the genetic code?

A

The instructions in a gene that tell a cell how to make a specific protein. Each gene’s code combines the four chemicals in various ways to spell out three-letter “words” that specify which amino acid is needed at every step in making a protein.

29
Q

What is a codon?

A

A triplet that encodes one amino acid

30
Q

What are the key features of the genetic code>

A

61 of a possible 64 codons code for an amino acid,
Most amino acids have more than one codon,
(UAG, UAG, UGA) codons specify stop
(AUG) codon specifies start as well as methionine.

31
Q

Structure of tRNA?

A

Transfer RNA is a single strand of RNA, there is at least one tRNA for each amino acid. Each tRNA has a region which can bind an amino acid AND a region which can interact with mRNA

32
Q

Role of tRNA in RNA synthesis?

A

tRNA acts as the adaptor. An enzyme (aminoacyl tRNA synthetase),recognises both a specific amino acid and the correct tRNA for this amino acid and joins them together

33
Q

What is Translation?

A

The synthesis of proteins by ribosomes using mRNA as a set of instructions

34
Q

Role of ribosomes in protein synthesis?

A

Ribosomes translate the genetic code transcribed in mRNA into an amino acid sequence

35
Q

Outline the relationship between genetic and phenotypic variation.

A

what happens at the DNA level is reflected at the protein level, and that genetic variation commonly leads to phenotypic variation

36
Q

Define allele?

A

Different form of a gene

37
Q

Describe the difference between genotype and phenotype?

A

Genotype is a set of genes and/or DNA
combinations that are responsible for a particular trait.
Phenotype is the physical expression, or characteristics of a genotype, i.e. are traits or characteristics of an organism that can be observed.

38
Q

What is Mendel’s 1st Law?

A

Segregation:

Genes segregate at meiosis so that each gamete contains only one of the two possessed by the parent

39
Q

What is Mendel’s 2nd Law?

A

Independent Assortment:

Alleles of different genes assort independently during gamete formation

40
Q

What is the sum rule?

A

the probability of the occurrence of one event or the other event, of two mutually exclusive events, is the sum of their individual probabilities

41
Q

What is the product rule?

A

the probability of two independent events occurring together can be calculated by multiplying the individual probabilities of each event occurring alone

42
Q

Polymorphic?

A

One gene that has many different alleles

43
Q

Co-dominance?

A

Both parental phenotypes are present in F!

44
Q

Incomplete dominance?

A

Both alleles of a gene are partially expressed, resulting in an intermediate phenotype.

45
Q

How do environmental factors effect phenotype?

A

Examples: Nutrition - height and weight, disease - life expectancy.

46
Q

What are sex linked trauts?

A

Involves genes on the sex chromosomes, their inherritanc epatterns differ between males and females.

47
Q

What are linked genes?

A

Genes that do not sort independently, and therefore are linked on the same chromosome.

48
Q

How does recombination occur for linked genes?

A

Crossing over during meiosis

49
Q

What is recombination frequency?

A

The proportion of recombinant gametes

50
Q

What is random genetic drift?

A

A random change in allele frequencies due to sampling

error over generation

51
Q

What is a population bottleneck?

A

Occurs when a species experiences an event that suddenly and significantly reduces it’s population

52
Q

What is the Founder Effect?

A

reduction in genetic variation that results when a small subset of a large population is used to establish a new colony.

53
Q

What is the effect of stabalising selection?

A

reduces variation but does NOT change the mean

54
Q

What is the Effect of Dissruptive selection?

A

favours the two extremes producing two peaks

55
Q

What is the effect of directional selection?

A

changes the mean value towards one extreme

56
Q

What is sexual selection?

A

Animals that express desired phenotypes for producing fit offspring will have better mating success.

57
Q

What is cline?

A

The gradual geographic change in genetic/phenotypic composition