Session 15-Mutations Flashcards Preview

Semester 1-MCBG > Session 15-Mutations > Flashcards

Flashcards in Session 15-Mutations Deck (27):
1

What is a mutation?

Change in a DNA sequence

2

What can mutations be a result of? (4)

DNA replication errors made during cell division (mitosis and meiosis)
Exposure to ionising radiation (mutagen)
Exposure to chemicals (chemical mutagens)
Infection by viruses

3

Where do germ line mutations occur?

In the eggs or sperm and affect all cells in the body and can be passed onto offspring

4

Where do somatic mutations occur?

In a body cell and isn't passed onto offspring

5

True or false: all mutations are bad

FALSE

6

Why are RNA translation errors common?

RNA polymerase do not proofread like DNA polymerase

7

True or false: long-term effects on an organism whose cell has made a transcription/translation error will not be as bad as if the mistake was in the genome itself

TRUE - multiple copies of RNA produced so unlikely that same mistake will be made twice, RNAs quickly degrade and RNAs are not inherited molecules

8

True or false: mitochondrial DNA (mtDNA) affects germ line and somatic mutations

TRUE

9

Which organs do mitochondrial diseases have the greatest effect on?

Heart, brain and muscles

10

What are some of the frequently observed features of mitochondrial disease?

Muscle weakness and wasting
Problems with movement
Diabetes
Kidney failure
Heart disease
Dementia
Hearing loss
Vision abnormalities

11

Why do mitochondrial somatic mutations build up over time?

mtDNA has limited ability to repair itself when it is damaged

12

What has a build up of somatic mutations in mtDNA been associated with?

Some forms of cancer and increased risk of age-related diseases such as heart disease, AD and Parkinson's

13

What are the three germ line mutations which lead to an incorrect DNA sequence? (Affects genes)

Substitution
Insertion
Deletion

14

What are the structural chromosomal germ line mutations?

Deletion
Duplication
Inversion
Translocation

15

What is the germ line mutation that affects the number of chromosomes?

Non disjunction

16

What is anaphase lag?

If the duplicate chromosomes do not pair properly at the metaphase plate, the pair won't move properly to each pole during anaphase, resulting in one cell having two copies of the chromosome while the other cell has none

17

What do primordial germ cells (PGCs) differentiate into in the foetal female gonad?

Oogonia

18

What is a primary oocyte surrounded by flattened epithelial cells called?

Primordial follicle

19

True or false: once PGCs arrive in the male gonad, they remain there until puberty

TRUE

20

How much sperm does a human male produce per day?

100 million

21

Why do PGCs in males only start to differentiate into spermatozoa at puberty?

They are only needed when oocytes are available to fertilise

22

Would you expect the IVF embryo aneuploidy rate to over or underestimate the in vivo rate?

Overestimate

23

What is a morula?

Solid ball of cells resulting from division of fertilised ovum

24

What could happen if a very early embryo was exposed to radiation (a mutagen)? (3)

Death/aborted
Teratogenesis
Cancer when born

25

What features would allow a germ cell mutation to be inheritable?

Not lethal to the gamete
Not impair gamete function
Not be lethal at fertilisation
Allow production of viable adult with normal reproductive capacity

26

Complete the sentence:

In general, recessive mutations cause loss of function and often affect ___________ pathways

Biochemical

27

Complete the sentence:

In general, dominant mutations cause increased function and often cause __________ ______________

Structural abnormalities