Brainscape's Knowledge GenomeTM

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


See full index

Principles > Genetics > Flashcards

Genetics Flashcards

1
Q

Each human has how many pairs of chromosomes?

A 
23 pairs (46 chromosomes in total)
22 autosomal pairs, 1 sex-linked pair
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

G0 phase of the cell cycle

A

Most cells are resting, carrying out their normal function

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

G1 phase of the cell cycle

A

1st growth phase as chromosomes become ready to be replicated

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

S phase of the cell cycle

A

DNA replication occurs

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

G2 phase of the cell cycle

A

2nd growth phase involving proteins etc.

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

M phase of the cell cycle

A

Mitosis - mechanical separation of cell into two daughter cells
Two daughter cells are identical, diploid cells

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

Variation occurs during meiosis by two main methods, which are?

A

Crossing over

Independent segregation of homologous chromosomes

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

In meiosis, one diploid cell becomes…

A

Four haploid daughter cells

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

Examples of sequence variations between genes?

A

Single nucleotide polymorphisms (SNPs)

Deletions/duplications

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

A polymorphism is…

A

A change in the genome that does not cause disease in its own right, but can predispose to a common disease

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

Chromosome 22 looks like a…

A

Teddy bear

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

A chromosome consists of…

A

Telomeres at each end
Short arm (p)
Centromere
Long arm (q)

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

A chromosome is metacentric if…

A

Both arms are roughly the same length

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

A chromosome is acrocentric if…

A

The p (short) arm is so short it is hard to observe

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

A chromosome is telocentric if…

A

The centromere is located at the terminal end of the chromosome

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

An aneuploidy is…

A

An abnormal number of chromosomes
Monosomy - missing chromosome from one pair
Trisomy - extra chromosome in a pair

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

Reciprocal translocations are when…

A

Segments from two different chromosomes have been exchanged

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

Robertsonian translocations are when…

A

A chromosome attaches to another chromosome at the centromere
Only occurs in acrocentric chromosomes: 13, 14, 15, 21, 22

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

Monosomy of the sex chromosomes causes…

A

Turner’s syndrome

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

Trisomy of chromosome 21 causes…

A

Down’s syndrome

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

What is FISH?

A

DNA probes specifically bind to areas of individual chromosomes and apply a fluorescein stain to make the chromosome visible
Useful for detecting aneuploidies

Must know where to ‘look’

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

Penetrance is defined as…

A

The likelihood of having the disease given you have the genetic mutation

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

Mendelian inheritance encompasses which disorders?

A

Autosomal dominant
Autosomal recessive
X-linked
Mitochondrial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Autosomal dominant disease occurs when…

A

There is one faulty copy of the gene
Seen in all generations
50% risk of affected child if parent affected

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

Autosomal recessive disease occurs when…

A

There are 2 faulty copies of the gene
Often only one generation affected
25% risk of affected child if parents are carriers
Increased likelihood if parents are related

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

X-linked disease occurs when…

A

The disease is carried on the X-chromosome only
50% of male children of a female carrier affected
50% of female children of a female carrier affected
All male children of a male carrier normal
All female children of a male carrier will be carriers

27
Q

Mitochondrial disease occurs when…

A

Diseased mitochondria passed from mother to child

28
Q

What is mosaicism?

A

Occurs when cells within the same person have a different genetic makeup

29
Q

Epigenetic variation describes…

A

Functional modifications to the genome that do not involve a change in the nucleotide sequence

30
Q

Methylation inhibits which process?

A

DNA transcription

31
Q

What is imprinting?

A

Variation in gene expression depending on which parent you inherit the gene from
e.g. in Angelman’s syndrome, mother’s UBE3A works fine but father’s is methylated

32
Q

Heteroplasmy is when…

A

Different daughter cells contain different proportions of mutant mitochondria (similar to mosaicism)

33
Q

Where are the 2 checkpoints in the cell cycle where DNA can acquire mutations?

A

Between G2 and M

Between G1 and S

34
Q

What is the function of proto-oncogenes?

A

Promote cell division

35
Q

What is the function of tumour suppressors?

A

Inhibit cell division

36
Q

Only one copy of the tumour suppressor gene is required to be mutated for cancer to occur. True/False?

A

False

2 copies required

37
Q

Cancer is most often inherited as a high penetrance Mendelian disorder. True/False?

A

False

More usually multifactorial

38
Q

Achondroplasia. Gene? Inheritance?

A

FGFR3

AD

39
Q

Turner Syndrome

A

45X

40
Q

How is the lagging DNA strand replicated?

A

Replicated in short Okazaki fragments in the 5’ → 3’

41
Q

What percentage of the genome are exons?

A

2-3%

42
Q

What is the most common base pair mutation?

A

Cytosine to Thymine

43
Q

Why do some females develop some feature of X-linked conditions?

A

X-inactivation via methylation

44
Q

Where does methylation (to turn of genes) usually occur?

A

Cytosine bases that occur directly before Guanine

45
Q

Which targeted therapy is used for BRAF oncogene mutations?

A

Vemurafenib

46
Q

Which targeted therapy is used for HER2 oncogene mutations?

A

Trastuzumab

47
Q

Which targeted therapy is used for philadelphia chromosome mutations?

A

Imatinib - protein kinase inhibitor

48
Q

What does the Rb gene encode?

A

Tumour suppressor proteins - located at G1 checkpoint

49
Q

When is karyotyping and chromosome analysis used?

A

For large (>5 million base-pairs) balanced translocations

50
Q

When is array-aCGH used?

A

Only detects imbalance (deletions or duplications)

51
Q

What is the disadvantage of using FISH?

A

You need to know where to look for the mutation

52
Q

When is PCR and Sanger Sequencing used?

A

When very small amounts of DNA need to be multiplied and sampled

53
Q

Which type of Next Generation Sequencing is most expensive?

A

Whole Genome Sequencing

54
Q

Which transcription factor aids all RNA polymerase II transcriptions?

A

TF IID

55
Q

How is pre-mRNA modified upon completion?

A

Poly - u - tail

56
Q

How is mRNA modified upon completion?

A

Poly - a - tail and a 5’-cap

57
Q

What does the term degenerate refer to in the genetic code?

A

Many amino acids have more than one corresponding codon

58
Q

In which direction is DNA polymerase’s exonuclease activity?

A

3’ -> 5’

59
Q

Which enzyme binds amino acids to their specific tRNA?

A

Aminoacyl-tRNA synthetases

60
Q

Which elongation factor brings the next aminoacyl-tRNA to the ribosomal A-site?

A

EF-1a

61
Q

Which elongation factor regenerates EF-1a after it is hydrolysed to EF by GTP?

A

EFßgamma

62
Q

Which enzyme catalyses the peptide bond between amino acids in the P and A-sites?

A

Peptidyl transferase

63
Q

Which elongation factor moves the ribosome along the mRNA?

A

EF-2

64
Q

How is the the peptide chain terminated in translation?

A

A-site encounters stop codon; RF binds GTP is hydrolysed and finished protein is cleaved off

Principles (9 decks)

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