Diagnostics Lec 2

Question 1

What is a codon

Answer 1

Three nucleotides linked together to form a unit of genetic doe in DNA/RNA

Question 2

what is a gene

Answer 2

basic unit of heredity

Question 3

what is an allele

Answer 3

two or more alterative forms of a gene

Question 4

what is a chromosome

Answer 4

condensed, threadlike structure of nucleic acids

Question 5

homozygous

Answer 5

having two identical alleles of a particular gene

Question 6

heterozygous

Answer 6

having two different alleles of a particular gene

Question 7

What is transcription

Answer 7

synthesis of RNA from a DNA template

Question 8

What is translation

Answer 8

Nucleotide sequence is translated to amino acid sequence

Question 9

Describe recessive genes in accordance to Mendelian inheritance

Answer 9

they are a variant if genes that only occur in homozygous

Question 10

Describe codominance

Answer 10

each variant of genes with same ability to express

Question 11

What makes a autosomal chromosome

Answer 11

the presence of genes for body function

Question 12

What is genotype

Answer 12

the genetic make up of an individual

Question 13

What is phenotype

Answer 13

The set of observable characteristics

Question 14

What is a trait in genetics

Answer 14

characteristic/feature of an organism

Question 15

What are genetic traits determined by

Answer 15

genes
- a functional unit of DNA
- locate on the chromosome in strict order

Question 16

How does sexual reproduction contribute to the variation of traits

Answer 16

Human cells have 46 chromosomes, 22 pairs are autosomes, 1 pair of sex chromosomes, alleles (homozygous/heterozygous)

Question 17

How does the Mendel method study inheritance

Answer 17

via mating/test cross

Question 18

Outline features of the Gregor Mendel method

Answer 18

• Carefully controlled experiments on plant hybrids
• cross pollinated true breeding strains
• Protect the experimental plants from accidental pollination by insects or the wind

Question 19

What are the two laws of single gene inheritance

Answer 19

Law of segregation
Law of independent assortment

Question 20

Describe the law of segregation

Answer 20

When an organism makes gametes, each gamete receives just one gene copy from each of the parent. The selection of gene copy from each parent is random

Question 21

Describe the law of independent assortment

Answer 21

The alleles of two (or more) different genes get sorted into gametes independently of one another

Question 22

When would an individual inherit homozygous genes?

Answer 22

if both alleles obtained from the father and mother are identical

Question 23

When would an individual inherit heterozygous genes?

Answer 23

If two of the alleles obtained from parents are different

Question 24

What is the normal version of a gene referred to as

Answer 24

wild type

Question 25

What is the mutated type

Answer 25

any changes that occur at the gene level due to mutation, normally leads to development of disease

Question 26

List types of gene mutation

Answer 26

Point mutation Deletion Duplication Inversion

Question 27

What are the three main types of mutation

Answer 27

Gene mutation Epigenetic changes Genetic disorder

Question 28

List types of genetic disorder due to mutation

Answer 28

Autosomal dominant disease Autosomal recessive disease Sex-linked inheritance

Question 29

Provide an example of an autosomal recessive disorder

Answer 29

Cystic fibrosis

Question 30

Outline the features of cystic fibrosis

Answer 30

- Presence of variants in both copies of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene - Caused by dysfunction of the chloride channels of exocrine glands - Resulted in abnormal viscous secretions in the airways of the lung and the ducts of the pancreas, and elevation of sodium and chloride concentration in sweat

Question 31

What are the main clinical manifestations of CF

Answer 31

- Recurrent lung infections - Exocrine pancreatic insufficiency - Male infertility

Question 32

What are the gene variants related to cystic fibrosis

Answer 32

cystic fibrosis gene is located at human chromosome 7q31.2 Encoded for a protein Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) The abnormal proteins could be found mainly in the lungs and pancreas, but also in the upper airways, liver, intestine, and reproductive organs

Question 33

Outline the features of Pedigree A autosomal recessive inheritance

Answer 33

Two distinct mutant alleles Heterozygous

Question 34

Outline the features of pedigree B autosomal recessive inheritance

Answer 34

Identical mutations Homozygotes

Question 35

The affected boy’s 20 year old sister is married to a man who is unrelated and with no family history of cystic fibrosis What is the chance of their children having cystic fibrosis?

Answer 35

1/3 (2 punnet squares x by eachother)

Question 36

Differences in sex chromosomes and how they affect inheritance

Answer 36

- Differ in size - Mail contains X and Y (hemizygous) - Female only X chromosomes (work as hemizygous, one X chromosome inactivated)

Question 37

Outline the features of X linked inheritance

Answer 37

Usually affects males Female often carrier (due to two X chromosome)

Question 38

Will people with a single mutation detected in one copy of the CFTR gene suffer from cystic fibrosis? Briefly explain your answer.

Answer 38

Patients with cystic fibrosis can experience symptoms ranging from mild to severe. What molecular factors explain this variation in disease severity? In your answer, consider how different mutations in the CFTR gene contribute to the clinical outcomes.