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Flashcards in Physiology - Genetics Deck (89)
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1
Q

Genome

  • how many pairs of chromosomes
  • contains what
  • intraspecies variation
A
  • 23 pairs of chromosomes
  • all genetic material in human cell
  • 0.1% variation
2
Q

Diploid vs. haploid

A

Diploid: (2n) both sets of of DNA

  • go through mitosis
    haploid: (n) one set of chromosomes
  • go through meiosis
3
Q

what type of cell is haploid

A

gametes - sex cells

4
Q

Genome

  • how many genes
  • what percentage of genome is coding
A
  • 20-25k genes

- 2% is coding

5
Q

what is the 98% of genome that is not coding?

A

“noncoding” but not junk

6
Q

Genome of eukaryote vs. prokaryote and implication

A

eukaryote - very little coding
prokaryote - 80% ish coding
-> level of complexity increases from pro to eukaryote

7
Q

List 3 types of non-coding region

A
  1. intron
  2. Intergenic DNA
  3. Functional RNA
8
Q

Intron

A
  • part of DNA/transcript that doesn’t code for anything that ends up in a protein
  • spliced out of transcriptional transcript before translation (mRNA processing)
9
Q

Intergenic DNA

A
  • DNA between genes

- doesn’t code for protein, participates in regulation

10
Q

4 types of Functional RNA

A
  1. Ribosomal RNA (rRNA)
  2. Transfer RNA (tRNA)
  3. Piwi-interacting RNA (piRNA)
  4. Micro RNA (miRNA)
11
Q

Piwi-Interacting RNA fxn

A

helps with regulation

12
Q

Micro RNA

A

helps prevent suppression of translation

13
Q

5 Types of Non-coding DNA

A
  1. Pseudogenes
  2. Cis and trans segments
  3. repeat sequences
  4. viral elements and transposons
  5. telomeres
14
Q

Pseudogenes

A

vestigial gene regions, from embryonic stage or evolutionary basis

15
Q

Cis and trans segments

A

complimentary bind to keep things open

16
Q

Viral elements and transposons

A

Transposons - segments of DNA that are inserted into DNA from the outside (ex from a virus)

9% of our genome is viral or transposon

Another way of recombination, can be bad

17
Q

telomeres

A
  • Long repeats at end of chromosomes

- Damage/shortening has to do with life cycle of the cell

18
Q

Mitochondrial DNA

  • how many genes
  • inheritance
A
  • 37 genes
  • maternal inheritance
  • make proteins from inside the mitochondria vs. make in cytosol and pump across the cell
  • Sperm only contribute DNA, egg has everything else including mitochondria :)
19
Q

DNA

- shape

A
  • double stranded helix
  • two strands run antiparallel
  • helical/spiral shape
  • nitrogenous bases line up
20
Q

Packing of DNA

A
  • DNA
  • DNA wraps around Histones
  • Chromatin
  • Chromosome
21
Q

What is form of active DNA during interphase

A

chromatin - serves as source of transcription

22
Q

During mitosis what configuration is DNA in

A

chromosome

23
Q

Chromosome can mean two things:

A
  1. one chromatid (not an “x”)

2. both sister chromatids (X shape) This just means the DNA has been replicated

24
Q

DNA replication

  • when
  • what happens
A
  • interphase, just before mitosis starts

- chromatin is highly condensed into chromosome form

25
Q

What holds two sister chromatids together

A

centromere

26
Q

If able to see DNA under light microscopy, what does that indicate?

A

can see chromosomes, means cell going through mitosis

27
Q

Karyotype

A
  • picture representation of all the chromosomes
  • pair homologous sets
  • 22 autosomes
  • 1 sex chromosomes (XX or XY)
  • look for deletions, duplications, what sex is the person
28
Q

main cause of human chrom. disorders

A

Nondisjunction:

  • Failure of homologous pairs to separate during Meiosis I
  • Failure of sister chromatid to separate during Meiosis II
29
Q

Down syndrome

  • aka
  • characteristics
  • susceptibilities
  • sexually
  • risk factors
A
  • Trisomy 21 (extra chrome 21)
  • facial features, short stature, heart defects, early Alzheimers, leukemia, usually intellectual deficiency
  • sexually underdeveloped, sterile
  • age of mother (older eggs) but can be nondisjunction of father’s chrome 21
30
Q

Patau Syndrome

  • aka
  • characteristics
  • stats
  • life expectancy
A
  • Trisomy 13
  • serious eye, brain, circulatory defects, cleft palate
  • 1:5,000 live births
  • rarely live more than a few months
31
Q

Edward’s syndrome

  • aka
  • characteristics
  • stats
  • life expectancy
A
  • trisomy 18
  • almost all organ systems affected
  • 1:10,000 live births
  • do not live more than a few months
32
Q

List 2 sex chromosome disorders

A
  • Klinefelter syndrome

- Turner sydnrome

33
Q

Klinefelter syndrome

  • number of chromosomes
  • characteristics
A
  • 47 XXY
  • male sex organs, small testes, sterile
  • breast enlargement, other feminine characteristics
  • normal intelligence
34
Q

Turner syndrome

  • number of chromosomes
  • stats
  • characteristics
  • how many make it to birth
A
  • 45 chromosomes 0X
  • 1:5000 live births
  • genetically female but don’t mature sexually during puberty, are sterile
  • short stature, normal intelligence
  • 98% die before birth
35
Q

What is significant about turner syndrome

A

only viable monody in humans

36
Q

Two chromosome deletion disorders list

A
  1. Cri du chat

2. Fragile X

37
Q

Cri du chat

  • what is genetic problem
  • characteristics
A
  • deletion of small portion chrom. 5

- severe mental retardation, small head with unusual facial features, cry sounds like distressed cat

38
Q

Fragile X

  • what is genetic problem
  • characteristics
  • stats
A
  • x chrome is fragile at one tip
  • usually have 29 repeats at this end of X but people with this syndrome have 700 due to duplications
  • 1:1500 males 1:2500 females
39
Q

What is most common form of mental retardation

A

Fragile X

40
Q

What is DNA backbone composed of

A
  1. Pentose sugar
  2. Nitrogenous base
  3. Phosphate group
41
Q

What link together in DNA strand (2)

A
  • phosphate groups like up and down chain

- base pairs H bond between strands

42
Q

RNA

- 3 major diff from DNA

A
  • uracil instead of adenine
  • ribonucleic acid not deoxyribonucleic acid
  • functions as single strand
43
Q

mRNA

A

transcript that codes for protein during translation

44
Q

tRNA

A

knows two languages - nucleic acid and amino acid, functions during translation

45
Q

what does semi-conservative mean in regards to DNA replication

A

DNA starts with two strands, each daughter cell gets one original strand and one replicated strand

46
Q

what enzyme works during DNA replication and what does it do?

A

DNA polymerase

  • opens DNA strands to create a reading section
  • links the new strands to the original strand
  • can find and fix DNA problems
47
Q

Transcription

  • where does it take place
  • what happens
  • what cell phase
  • enzyme
A
  • in nucleus
  • coding region of DNA is transcribed into mRNA which later translates into protein
  • interphase
  • RNA polymerase
48
Q

Translation

  • what happens
  • what RNA involved
A
  • large and small ribosome units come together and protect mRNA transcript, provides reading frame to create proteins
  • rRNA, mRNA, tRNA
49
Q

what bond is made between amino acids during translation

A

peptide bonds

50
Q

Cell cycle

  • what stages during interphase
  • other phase
A
  • G1, S, G2 during interphase

- mitosis is other stage

51
Q

what happens right before mitosis

A
  • replicate DNA
  • condense DNA into chromosomes
  • nuclear membrane breaks down
52
Q

Mitosis

  • definition
  • what type of cell
  • what type of daughter cell is created
A
  • somatic cell division to produce two identical daughter cells/clones
  • somatic cells
  • diploid cells created
53
Q

what is function of mitosis

A
  • development
  • growth
  • cell replacement of damaged cells
54
Q

Stages of mitosis

A
  • prophase
  • metaphase
  • anaphase
  • telephase and cytokinesis
55
Q

Prophase

A
  • chromatin coil to form chromosomes
  • nuclear membrane breaks down
  • centrioles divide, start to migrate to opposite sides of the cell
  • centrioles start to make spindle fibers
56
Q

Metaphase

A
  • Chromosomes line up in the middle along equatorial plate
  • Lined up by microtubules
  • Centrioles are at outer poles, spindle fibers attach to chromosomes
57
Q

Anaphase

A

Spindle fibers are reeled in by centrioles, pull each sister chromatid to separate sides

58
Q

Telephase & cytokinesis

A
  • Create cell cytoplasm, cytokinesis
  • Rebuild nuclear membrane
  • Get two identical daughter cells
59
Q

Meiosis

  • what is created
  • two stages and overview of what happens
A
  • 4 haploid gametes
  • Meiosis I - tetrads separate
  • Meiosis II - sister chromatid separate
60
Q

Meiosis I

A
  • Chromosomes replicate
  • Line up homologous pairs of chromosomes and separate
  • Crossover (recombination) of homologous pairs (one from mom and one from dad). Form tetrads - entangle and divide chunks of DNA. This helps with genetic variation
  • At the end have two haploid daughter cells
61
Q

Meiosis II end brief overview

A

Separate sister chromatid to end up with a total of 4 haploid daughter cells

62
Q

Major difference between Meiosis I and Meiosis II

A

prophase - tetrads switch genetic information

63
Q

Metaphase in Meiosis I vs. II

A

I - whole pairs are separated
II - sister chromatid are separated
(both during anaphase)

64
Q

spermatogenesis vs. oogenesis

A

spermatogenesis - 4 equal sperm

oogenesis - one big egg and 3 polar bodies

65
Q

fertilization

A

two haploid cells (sperm and egg) going to make one diploid cell

66
Q

Mendelian principle of dominance

A

if two forms of a gene are present, the dominant allele is expressed

67
Q

Mendelian principle of segregation

A

in meiosis, two alleles separate so that each gamete receives one form of the gene

68
Q

Mendelian principle of independent assortment

A

each trait is inherited independent of other traits

69
Q

Allele

A

form of a gene

70
Q

Gene

A

segment of DNA that form a protein

71
Q

homologous alleles

A

two versions of the same gene

72
Q

phenotype

A
  • phenotype: what it looks like, what you can see (curly or straight)
  • even if you can’t see it like metabolic activity
73
Q

genotype

A
  • what is written in the genes, what two alleles are present

- homozygous dominant, homozygous recessive, heterozygous

74
Q

Sex linked chromosomes

A
  • allele is carried on sex chromosome.
  • creates gender differences in inheritance
  • if deleterious, more often show up in male offspring (only in daughter if both father and mother are affected)
75
Q

Incomplete dominance

A
  • Three genotypes and three phenotypes
  • hair wave is an example: straight, curly, somewhere in-between
  • flowers: red, pink, white
76
Q

Codominance

A
  • nothing is hidden, everything is expressed, both alleles are expressed
  • blood type is an example, A, B, AB
77
Q

Multiple alleles

A

two or more alleles for a trait, blood type example

78
Q

Polygenic traits

A

multiple genes for a trait - skin or hair color are examples, get a wide range

79
Q

PKU

A
  • genetic disease
  • autosomal recessive
  • 1:25,000
  • metabolic disorder
  • results in toxic levels of phe and decreased level of tyr
  • developmental issues, seizures, microencephaly, decreased cerebral fn
  • hypo pigmentation
  • do a newborn screening, if have, reduce phe in diet
80
Q

Sickle cell anemia

A
  • autosomal recessive
  • incomplete dominance: shows a spectrum of affect
  • single nucleotide defect
  • decreased O2
  • chronic or acute
81
Q

Sickle cell trait

A
  • heterozygous have 40% Hbs
  • resistance to malaria (benefit)
  • 2.5 million in US
82
Q

Cystic fibrosis

A
  • autosomal recessive
  • mutation in channel protein of sweat and mucous glands
  • increased thickness of secretions
  • respiratory, digestive issues and pancreas involvement
  • 30 year average life expectancy
83
Q

Polycystic kidney disease (PKD)

A
  • autosomal recessive and autosomal dominant forms (recessive is more common)
  • two forms: AD and AR
  • nephron cell mutation
  • HTN, HA, abd pain, hematuria, polyuria, back pain, kidney failure
  • appears in 40-60 yo
84
Q

Hemophilia

A
  • A most common, also b and C (least common)
  • impaired clotting cascade
  • sex linked recessive (seen more often in males)
85
Q

Neurofibromatosis

A
  • three types
  • tumors in skin, skeletal deformities, freckled pits and groin
  • children with >6 cafe au lait spots are higher risk
86
Q

Congenital disorders

A
  • aka birth defects
  • exist at birth
  • ex. heart disease and neural tube defects
87
Q

Teratogenesis

A

environmental factors affect in utero growth and development

88
Q

what does susceptibility of teratogenesis depend on?

- varies with what

A
  • genotype of the conceptus and interaction with adverse environmental factors
  • varies with developmental stage at time of exposure (some critical periods exist)
89
Q

Four manifestations of deviant development

A
  1. death
  2. malformation
  3. growth retardation
  4. functional defect