Genetics

Question 1

Genotype vs phenotype

Answer 1

Genotype = genetic make-up, the letters

Phenotype = physical expression, what we can see

Question 2

Describe Segregation. What happens if there’s an error in segregation?

Answer 2

2 alleles of 1 particular trait will be separated & distributed to 2 different daughter cells

ex: Jj; allele J will go to 1 daughter cell & allele j will go in other

Errors= cancer, infertility, down syndrome

Question 3

What happens during crossover?

Answer 3

aka chiasma

homologous chromosomes can break, & cross over resulting in recombinant chromosomes (mixture of combos from each parent)

Question 4

Describe incomplete dominance. An example?

Answer 4

heterozygous indiviuals have intermediate phenotype

they might have sxs but not as intense

ex: sickle cell

Question 5

Multiple-allele inheritance example?

Answer 5

Blood typing

genes that exhibit 1+ allele

Question 6

Describe sex-linked inheritance

Answer 6

inherited traits determined by genes on sex chromosomes (XX or XY)

Question 7

X chromosomes bear over _____ genes while Y chromosomes carry about ____

Answer 7

X = 1400+
Y = 200

Question 8

Genes found only on X chromosome are called

Answer 8

X-linked genes

Question 9

X-linked RECESSIVE alleles are ALWAYS expressed in _____

Answer 9

males; bc there is no Y counterpart

Question 10

Females must have recessive alleles on_______ in order to express an X-linked condition

Answer 10

both X chromosomes

Question 11

What conditions are passes from mothers to sons? (hemophilia, red-green color blindness)

Answer 11

X-linked recessive conditions

Question 12

A female who is a carrier (heterozygous) for red-green color blindness + male w normal color vision are going to have a boy baby.

What is the % of the boy having colorblindness?

Answer 12

50%

Question 13

A female who is a carrier (heterozygous) for red-green color blindness + male w normal color vision are going to have a boy baby.

What is the % of the offspring having colorblindness?

Answer 13

25%

Question 14

A female who is a carrier (heterozygous) for red-green color blindness + male w normal color vision are going to have a boy baby.

What is the % of the female baby being a carrier of colorblindness?

Answer 14

50%

Question 15

Name the 3 levels of control found in the human genome

Answer 15

1st layer: protein coding genes
2nd layer: small noncoding RNAs
3rd layer: epigenetic marks

Question 16

The 1st layer of control involves ____ & is involved in what % of a cell’s DNA?

Answer 16

“protein coding genes”

DNA that is “blue print” for protein synthesis, that is actually synthesized

less than 2%

Question 17

The 2nd layer of control is found ____ & is involved in what % of a cell’s DNA?

Answer 17

“small noncoding RNAs”

non-protein-coding DNA

80% of genome

Question 18

The 3rd layer of control is stored in ____ that binds to ____ & affects what?

Answer 18

“epigenetic marks”

stored in proteins & chemical groups

binds to DNA

affects how chromatin are packaged

Question 19

All DNA is in the

Answer 19

nucleus

Question 20

The most common small noncoding RNA is

Answer 20

microRNAs (miRNAs)

Question 21

Small noncoding RNA function

Answer 21

reduce expression of particular genes

joins w enzymes to silence genes

Question 22

What are transposons & what inactivates them? When is it important?

Answer 22

genes that tend to replicate themselves & insert themselves into distant DNA sites = disabling or hyper-activating genes

small non-coding RNAs inactivates

normally during development, fight off viral infections

Question 23

Mutations in sncRNAs have been implicated in

Answer 23

cancers & schizophrenia

Question 24

Certain chemical tags determine whether DNA is available for transcription (____) or silenced (______)

Answer 24

transcription = acetylation

Silenced = methylation

Question 25

Describe genomic imprinting

Answer 25

certain genes tagged w methyl groups during gametogenesis to ID as maternal or paternal

Question 26

There are ____ mitochondrial DNA & it is inherited from the ___ ONLY

Answer 26

37; mother ONLY

Question 27

What are some rare d/o linked w errors in mtDNA?

Answer 27

Problems w oxidative phosphorylation (cellular respiration)

Muscle/neurological problems (alzheimers, parkinson’s)

Question 28

Mnemonic for Autosomal Dominant D/Os

Answer 28

Very Powerful DOMINANT Humans

only 1 gene/allele needed to be expressed

Von willebrand dz
Psuedo-hypoparathyroidism
Dystrophia myotonic
Osteogenesis imperfecta
Marfan syndrome
Intermittent porphyria
Neurofibromatosis
Achondroplasia/Adult PCKD
Noonan syndrom
Tuberous schlerosis
Hypercholesterolemia
Huntington’s
Hypertrophic obstructive cardiomyopathy
Hereditary spherocytosis
Hereditary non polyposis coli
Hereditary hemorrhagic telangiectasi

Question 29

Mnemonic for autosomal RECESSIVE d/o

Answer 29

ABCDEFGH
Albinism, Ataxia
Beta thalassemia
Cystic fibrosis & congenital adrenal hyperplasia
Distal spinal muscular atrophy
Emphysema (alpha-1 antitrypsin def)
Friedreich ataxia
Galactosemia & glycogen storage d/o
Hemochromatosis

Question 30

X-LINKED recessive d/o

Answer 30

GRHBE

G6PD Def
Retinitis pigmentosa
Hemophilia
Blindness
Ehler’s Danlos

Question 31

CFTR gene on chromosome 7 = what condition

autosomal ____

Answer 31

cystic fibrosis

autosomal recessive

Question 32

DMD (dystrophin gene) = what condition

Answer 32

duchenne MD

x-linked recessive

Question 33

What 4 conditions have trisomal gene repeats?

Answer 33

Fragile X, huntington, friedreich ataxia, myotonic dystrophy

Question 34

What conditions are trisomies?

Answer 34

Down syndrome (21)

Edwards syndrome (18)

Patau syndrome (13)

Question 35

Short arm on chromosome 5 deletion

Answer 35

Cri-du-chat syndrome

Question 36

What condition has XXY?

Answer 36

klinefeiter’s syndrome

Question 37

Deletion on chromosome 22 = what condition?

Answer 37

Digeorge syndrome

Question 38

BRCA mutation

Answer 38

breast cancer

Question 39

HFE

Answer 39

Hemochromatosis