genetic methods

Question 1

what is genetic research?

Answer 1

• study of heredity
• how traits are passed from generation to generation

Question 2

define genotype

Answer 2

• underlying biological makeup

Question 3

define phenotype

Answer 3

• observable traits

Question 4

who is Gregor Mendel?

Answer 4

• cited to be the first geneticist

Question 5

define dominant

Answer 5

• traits that only require one allele to be expressed
• these will be the organisms phenotype

Question 6

define recessive

Answer 6

• requires two alleles to be expressed
• only expressed when there is no dominant trait

Question 7

define allele

Answer 7

• version of a gene
• either dominant or recessive

Question 8

what 2 fundamental laws does Mendelian inheritance rely on?

Answer 8

1/ segregation
- traits either dominant or recessive

2/ independence
- varieties of each trait sort independently of each other

Question 9

where is DNA found?

Answer 9

• nucleus

Question 10

what is DNA composed of?

Answer 10

• 2 chains of nucleotides
• these coil around each other
• forms double helix

Question 11

what does the double helix contain?

Answer 11

• genetic instructions for development, functioning, growth, reproduction of all known biological organisms

Question 12

how are protein strands made?

Answer 12

• double helix = unzipped
• read by RNA molecules
• process = translation

Question 13

what are the 4 bases?

Answer 13

Adenine
Guanine
Cytosine
Thymine

Question 14

define chromatids

Answer 14

• long strand of DNA
• found in nucleus
• coil during cell division to form chromosome

Question 15

describe what happens to chromatids during cell division
(DNA to chromosome)

Answer 15

• chromatids undergo condensation
• coil together
• forming chromosome

Question 16

how many chromosome in a typical human?

Answer 16

46 (23 pairs)

Question 17

what are all pairs of chromosome aside from one?

Answer 17

• all are XX
• final pair varies

Question 18

what does the final pair of chromosomes code for?

Answer 18

• biological sex
• either XX or XY

Question 19

define gene

Answer 19

• describes single strand of functional DNA on a chromosome

Question 20

how many genes do humans possess?

Answer 20

between 20,000 to 25,000

Question 21

define genome

Answer 21

a collection of genes

Question 22

define pleiotropic

Answer 22

• where phenotypic traits = programmed by single gene

Question 23

define polygenic

Answer 23

• where phenotypic traits = influenced by combination of genes

Question 24

why study genetics?

Answer 24

• help understand genetic disorders
• greater understanding of biology

Question 25

what are X-linked genes

Answer 25

- where some recessive traits more commonly expressed in males compared to females - due to males not having a dominant allele on their (much shorter) Y chromosome

Question 26

what are sporadic mutations?

Answer 26

- occurs as a result of errors in typical cell division - mutations happen naturally - or mutations happen as result of environmental factors (e.g.: radiation)

Question 27

what are polygenic traits?

Answer 27

- traits that rely on coding from multiple genes - may not follow Mendelian rules - many genetic disorders considered to be polygenic in nature

Question 28

give examples of X-linked genetic disorders

Answer 28

- colourblindness - Turner Syndrome (effect females with only one X chromosome) - Klinefelter Syndrome (effects males with additional X chromosome) - Fragile X syndrome

Question 29

give example of genetic disorder that occurs due to sporadic mutation

Answer 29

Down's Syndrome - extra chromosome (due to errors in segregation of alleles) Williams Syndrome - due to micro-deletion on chromosome 7

Question 30

give example of genetic disorder that occurs due to polygenic traits

Answer 30

schizophrenia - not a single gene causes this - but individual considered to be genetically predisposed to develop this (may have trait but not show signs of it) - has clear genetic link

Question 31

how have genetic conditions been studied?

Answer 31

- twin studies - monozygotic twins = twins from same egg, 100% share DNA (genetically identical) - dizygotic twins = twins from separate egg, 50% DNA

Question 32

what are genomic studies?

Answer 32

- inspects genome of specific groups - help identify allele commonalities (looking at what is consistent across them)

Question 33

what are targeted mutations?

Answer 33

- mutated lab produced genes inserted into chromosomes - there are two types

Question 34

what are the two types of mutated lab produced genes that are inserted into chromosomes?

Answer 34

- knockout genes - knock-in genes

Question 35

what are knockout genes?

Answer 35

- mutated lab produced genes that fail to produce specific functional protein

Question 36

what are knock-in genes?

Answer 36

- mutated lab produced genes that can produce specific functional protein

Question 37

what is genetic engineering?

Answer 37

- where we can edit our own genome - currently being used to tackle HIV and cancer