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Flashcards in Genetics Deck (40):
1

Which direction is DNA replicated in?

A 5 to 3 direction

2

How many bonds are present between Adenine and thymine?

Two

3

How many bonds are present between guanine and cytosine?

Three

4

Which base is replaced in RNA and what with?

Thymine is replaced by uracil

5

When does cell division occur?

During mitosis

6

When does DNA replication occur?

During the S phase

7

What is an exon?

Coding part of a gene

8

What is an intron?

Non-coding part of a gene

9

What is a polymorphism?

A variation in the human genome that does not cause a disease in its own right

10

What is a mutation?

A gene change that causes a genetic disorder

11

What is an Achrocentric chromosome?

A chromosome where the short arm is either non-existent or so small its insignificant

12

Define aneuploidy

Whole extra or missing chromosome

13

Define translocation

Rearrangment of chromosomes

14

What is a Robertsonian translocation?

Two achrocentric chromosomes stuck end to end

15

What is a reciprocal translocation?

When the bottom of two adjacent chromosomes are attached to each other

16

Define somatic mosaicism

One genetic change that contributes to a disease

17

Which test is used for big genetic changes?

aCGH - deletions and duplications

18

Which test is used for small genetic changes?

PCR then sanger sequencing - one base change

19

Mutation

A genetic variation that causes a disease

20

Polymorphism

A genetic variation that is prevalent in the population and is not itself disease causing

21

Is PCR used when a specific part of the the genome needs to be looked at or is the section unknown?

Specific part

22

Missense

Change in one base

23

Insertion

Adds one base

24

Deletion out of frame

Deletes one base

25

Deletion in frame

Deletes three bases

26

What is the only thing aCGH detects?

An imbalance

27

Penetrance

The likelihood of having the disease if you have the gene mutation

28

Do mendelian disorders have a high or low penetrance?

High

29

What is the mechanism of x-inactivation?

Methylation

30

Single nucleotide polymorphism (SNP)

Alterations in the DNA sequence which occurs in every 100 to 300 base pairs

31

Copy Number variants (CNV)

Extra or missing stretches of DNA - deletions or duplications

32

Sequence variations within a gene

Promotor sequence
Exon sequence
Change in amino acids
Unchanged amino acids

33

Sequence variations in DNA between genes

Single nucleotide polymorphism
Copy Number Variants

34

4 Types of non-mendelian inheritance

Multifactorial
Imprinting
Mitochondrial
Mosaicism

35

Where does methylation occur?

On the cystine base before guanine

36

What does methylation prevent?

Transcription

37

Imprinting

Difference in gene expression depending on whether the gene is maternally or paternally inherited

38

What is the most common base mutation?

C to T

39

Which parent is most mitochondrial disease inherited from?

Mother

40

Heteroplasmy

Different daughter cells have differing levels of mutated mitochondria