Lecrture 6

Question 1

What is a locus?

Answer 1

The chromosome location of a specific gene

Question 2

What is a allele?

Answer 2

The different forms of a gene or DNA sequence

Question 3

What is a gene?

Answer 3

= Sequence of DNA or RNA that contains a code for one protein or RNA molecule

Question 4

Homozygote?

Answer 4

two alleles at the locus are the same

Question 5

Heterozygote?

Answer 5

Two different alleles at the locus

Question 6

Hemizygote?

Answer 6

unpaired genes in an otherwise diploid cell

Question 7

What types consists of most of the allele types?

Answer 7

Wild-types

Question 8

What are allele variants?

Answer 8

Different from the wild-type due to permanent changes in nucleotide sequence or arrangement in DNA sequence

Question 9

What is mutation?

Answer 9

A process! All genetic variation originates from the process known as mutation, which lead to alteration in human genome

Question 10

Alterations in human genome can be observed in which two levels?

Answer 10

Chromosomal aberrations ( numerical and structural )
or
Alteration of DNA sequence

Question 11

Errors in DNA replication? (DNA polymerase)

Answer 11

DNA polymerase can add wrong nucleotides.

But it has a proof reading activity, so it can check the mistakes

Question 12

What is exonuclease activity?

Answer 12

DNA polymerase moves back, deletes wrong ones, add new nucleotides

Question 13

Errors in DNA replication? (slippage)

Answer 13

Repeated units (microsatellites) of DNA sequence may result in replication slippage
Can add extra repeate to the strand -> one new molecule with additional unit

Question 14

What is DNA reparation?

Answer 14

if DNA polymerase cant correct the mistake, miss match repair comes to a place -> recombination repair

Question 15

Errors in recombination during the cell division

Error in cell division, structure or chromosomal number changes

Answer 15

Yepyep

Question 16

Induced process of mutation by environmental factors example?

Answer 16

Physical
Chemical
Biologocal – transposons, viruses: duplication or position change of a sequence

Question 17

Base substitutions?

Alteration of DNA sequence: Type of allelic variants and their consequences

Answer 17

Substitutions within coding

Question 18

Missenses?

Alteration of DNA sequence: Type of allelic variants and their consequences

Answer 18

Single nucleotide substitution in coding region, which alters the genetic code BY:
Nonsynonymous replacement of one amino acid.

Example TGG Trp instead of the widtype that has CGG Arg

Question 19

Silent?

Alteration of DNA sequence: Type of allelic variants and their consequences

Answer 19

Single nucleotide substitution in coding region, which alters the genetic code BY:
synonymous replacement of one amino acid

Question 20

Nonsense?

Alteration of DNA sequence: Type of allelic variants and their consequences

Answer 20

Single nucleotide substitution in coding region, which alters the genetic code by producing one of the three stop codons in the mRNA

Question 21

Affecting RNA transcription?

Answer 21

occurs at exon-intron or intron-exon boundaries, alter the splicing signal that is necessary for proper excision of an intron

Question 22

Deletions?

Answer 22

loss of one or more base pairs

Question 23

Insertions?

Answer 23

Insertion of one or more base pairs

Question 24

Insertions of mobile elements?

Answer 24

insertion of a LINE and SINE repeats -> frame shifts

Question 25

Dinamic mutation?

Answer 25

more simple nucleotide sequences repeated -> next generation gets more repeates

Question 26

Gain-of-function? | Consequences of allelic variants in functional level

Answer 26

variants lead to a completely new protein product, with new function or over expression, or inappropriate expression

Question 27

Loss of function? | Consequences of allelic variants in functional level

Answer 27

loss of gene product activity

Question 28

Dominant negative? | Consequences of allelic variants in functional level

Answer 28

abnormal protein interferes with the wild-type protein product and inhibit its function

Question 29

Aneuploidy? | Numerical abberration

Answer 29

- loss or gain of one chromosome (2n -1 or 2n +1) - Missegredation of a chromosome pair during Cell division - Changes during germ cell division are responsible for conditions such as trisomy 21 - Chromosomal aneuploidy are the most common changes seen in humans - Rate of abberration is one per 25-50 cell cycles

Question 30

Polyploidy? | Numerical abberration

Answer 30

- Europloidy – n – complete set of chromosomes - Polyploidy – 3n – (triploidy = 69 chromosomes), 4n – (tetraploidy = 92 chromosomes) - Failure in meiotic or mitotic cell division

Question 31

Rearrangement of structure or regional organisation of chromosomes can be? (Structural abberration)

Answer 31

Unbalanced – loss of gain or genetic material | Balanced – might be harmful in cell division phase

Question 32

Deletion? (Chromosome breakage) | Structural abberration

Answer 32

chromosome break and loses genetic material - loss of chromosome’s tip = terminal deletion - two breaks = interstitial deletion - Deletion in both tips = ring chromosome

Question 33

Translocation? (Chromosome breakage) | Structural abberration

Answer 33

interchange of genetic material between non-homologous chromosomes - resulting chromosomes are called derivative chromosomes - Types of translocations – reciprocal and robertsonian

Question 34

Inversion? (Chromosome breakage) | Structural abberration

Answer 34

result of two breaks on a chromosome followed by the re-insertion of the intervening fragment at its original site but inverted by 180-degree - inversion including centromere = pericentric invertion

Question 35

Duplication? (Chromosome breakage) | Structural abberration

Answer 35

gain of genetic material | - less serious consequences than deletions