Biology 101 Exam 2

Front 1

Asexual Reproduction

Back 1

One parent gives to offspring that are IDENTICAL to the parent

Front 2

Who uses Asexual Reproduction?

Back 2

Prokaryote
single celled eukaryotes (yeast, euglenas)
single celled protists
multicellular (star fish plants)

Front 3

What is the consequence of asexual reproduction?

Back 3

All offspring are genetic equals (not much variation)

Front 4

Sexual Reproduction

Back 4

Two parents, offspring are different from each other and parents

Front 5

The two phases of eukaryotic cell cycle

Back 5

Interphase
Mitosis

Front 6

What are the 3 subphases of interphase?

Back 6

1) G1
2) S
3) G2

Front 7

G1 (Gap 1)

3 things

Back 7

1) before dna synthesis
2) increase in cell organelles
3) general growth

Front 8

S (Synthesis)

3 things

Back 8

1) DNA replication occurs
2) Chromosomes replicate and remain joined to their replicated partner (sister chromatids)
3) More cell growth

Front 9

G2 (Gap 2)

3 things

Back 9

1) After DNA synthesis
2) Increase in protein synthesis
3) General metabolic activity (making ATP) and growth

Front 10

Mitosis (M) 4 subphases

Back 10

1) prophase
2) metaphase
3) anaphase
4) telephase

Front 11

90 percent of the cells time is in what phase?

Back 11

Interphase

Front 12

Interphase prcedes what two processes?

Back 12

mitosis and meiosis

Front 13

Prophase
4 things

Back 13

1) DNA condenses (coils) becomes visiible in light microscope

2) Nuclear envelope and nucleolus disappear

3) spindle- begins to form (microtubules) --attaches to kinetochore, centrosome

4) sister chromatids (replicated chromosomes) move towards the equator of cell

Front 14

This is what one end of a spindle joins to, its located at the centromere of each chromatid

Back 14

kinetochore

Front 15

The other end of a spindle joins to this microtubule organizing center?

Back 15

centrosome

Front 16

Metaphase "midway"
3 things

Back 16

1) Sister chromatids are at metaphase plate (equator)

2) Spindle is completed

3) nuclear envelope is completely gone

Front 17

If spindle fibers at the equator are not attached to chromatids, what are they attached to?

Back 17

Other fibers originating at the opposite pole

Front 18

Anaphase
3 things

Back 18

1) sister chromatids seperate and become chromosomes and go to opposite poles

2) spindles shorten (attached to chromosomes)

3) spindles lengthen (attached to other fibers) causing the cell to elongate

Front 19

When does telophase (cytoskinesis) begin?

Back 19

once all chromosomes are at spindle poles

Front 20

Telophase/cytokinesis
(4) things)

Back 20

1) DNA- uncoil

2) Nuclear envelopes and nucleoli reappear

3) spindle disappears

4) cytokinesis cell divides into two

Front 21

Cytokinesis (cell divides into two) in animals

Back 21

"cleavage"
ring of microfilaments pinch cell in middle, and cytoplasm divides into two cells

Front 22

Cytokinesis (cell divides into two) in plants

Back 22

"Cell plate formation"

Fusion of vesicles filled with cell wall materials at the equator forms two cells

Front 23

Two types of proteins that are "doers" of the cell cycle

Back 23

1) kinases
2) growth factors

Front 24

Kinases

Back 24

enzymes that add phosphates to other proteins

Front 25

Growth factors

Back 25

proteins that activate various genes telling the cell to grow and divide

Front 26

Two classes of "checkpoint" gene products (proteins) that regulate mitosis?

Back 26

1) proto-oncogenes
2) tumor suppressors

Front 27

Which checkpoint class is like the gas in a car?

Back 27

proto-oncogenes

Front 28

Which checkpoint class is like the brakes in the car?

Back 28

tumor suppressors

Front 29

3 major characteristics of all malignant neoplasms (cancers)

Back 29

1) grow and divide abnormally
2) cytoplasm and plasma membrane become altered, cytoskeleton shrinks
3) weakened capacity to adhere

Front 30

What kind of impact does cancer have on the developed world in terms of the cause of death?

Back 30

causes 15-20 percent of all death

Front 31

Why does a drug like taxol work to kill cancer cells?

Back 31

It keeps microtubules from diassembling and hampers mitosis

Front 32

How many new cases of breast cancer are diagnosed in the U.S. each year?

Back 32

200,000

Front 33

What kind of proteins are BRCA-1 and BRCA-2?

Back 33

Tumor suppressor

Front 34

Normall, BRCA proteins bind to receptors that then do what?

Back 34

Regulate the transcription of growth factor genes

Front 35

How is this process altered when there is a mutant BRCA protein?

Back 35

Growth factors are overproduced because BRCA cannot bind to the receptors. Cell division goes out of control, and tissue growth becomes disorganized which leads to cancer

Front 36

According to may sources including the American Society of Breast Surgeons, the risk of getting breast cancer if a woman inherits a mutant BRCA gene is what?

Back 36

80 percent

Front 37

What is the estimated risk of getting breast cancer for the average woman?

Back 37

12 percent

Front 38

Gamete

Back 38

a sex cell(sperm or egg)
meiosis of diploid cell

Front 39

Somatic cell

Back 39

Any cell that is not a gamete
It is mitosis of a diploid cell

Front 40

Homologous chromosomes

Back 40

two chromosomes that are nearly identical (one from mom one from dad), same location, different "versions"

Front 41

Autosomes

Back 41

22 autosomes means 22 pairs of homologous chromosomes

Front 42

Sex chromosomes

Back 42

xx-female
xy-male

Front 43

Which pair is the sex dermining pair in chromosomes?

Back 43

23rd pair

Front 44

Diploid cells

Back 44

two sets of chromosomes (2n)

Front 45

Haploid cells

Back 45

A single set of chromosomes

Front 46

Meisos: chromosomes number is reduced by?

Back 46

one diploid cell gives rise to 4 haploid cells

Front 47

What cells use Meiosis?

Back 47

specialized diploid reproductive cells in testes and ovaries

Front 48

What is the purpose of Meiosis (2)?

Back 48

1) Keep the chromosomes # from doubling each generation

2) Produce variation "shuffle the alleles

Front 49

Meiosis stages

Back 49

1) interphase (GI,2,G2)
2) Prophase 1
3) Metaphase 1
4) Anaphase 1
5) Telophase 1 and cytokinesis
6) prophase II - Telephase II

makes 4 haploid cells

Front 50

Is interphase the same in mitosis and meiosis?

Back 50

yes

Front 51

What is different in prophase I than prophase of mitosis?

Back 51

1) chromatids align as tetrads
4 chromatids= replicated homologs

2) synapsis = crossing over
occurs

3) hybrid chromosomes = result of crossing over

Front 52

What is different in metaphase I than metaphase of mitosis?

Back 52

1) tetrads line up at metaphase plate
2) tetrads are attached to spindle fibers

Front 53

Anaphase I

Back 53

homologs separate from each other

Front 54

Telophase I and cytokinesis

Back 54

1) spindle disappears
2) nuclear envelopes and nucleoli- reappear (some species)
3) DNA- may uncoil (some species)
4) Cytokinesis results in 2 cells (sister chromatids still joined)

Front 55

Prophase II-Telophase II

Back 55

Same of mitosis, sister chromatid separate and produce four cells

Front 56

Is there interphase between meiosis I and meisos II?

Back 56

NO

Front 57

What separates in meiosis one?

Back 57

homologs seperate (2 cells form)

Front 58

What separates in meiosis two?

Back 58

sister chromatids seperate (4 cells form) HAPLOID

Front 59

Independent Orientation

Back 59

Orientation of homologs at metaphase I (Meiosis 1) plate

Front 60

According to Independent Orientation how many total number combinations in a diploid cell? formula?

Back 60

2 raised to n (number of pairs of chromosomes-combindations)

Front 61

How many total combinations would there be in humans? According to indepedent orientation?

Back 61

2 raised to 23

8 million

Front 62

Random fertilization

Back 62

Fusion of the haploid nuclei of two gametes. This is where chromosome number is restored.

Front 63

Formula for random fertilization

Back 63

(2^n) (2^n)

Front 64

According to random fertilization how many combination's in a human?

Back 64

64 trillion combinations

Front 65

What leads to genetic variability (meiosis)?

Back 65

1) indepedent orientation
2) random fertilization
3) crossing over during synapsis of PROPHASE 1- random occurs approximately 1 to 2 times per homolog pair

Front 66

Principle of segregation
Gregor Mendel

Back 66

Diploid cells have pairs of genes on pairs of homologous chromosomes.

The two genes of each pair are segregated-seperated from each other during meiosis so they end up in different gametes

Front 67

Genes

Back 67

unit of information about specific traits
ex: pea color

Front 68

Humans have about how many genes spread out among their 23 chromosomes?

Back 68

22,000 genes

Front 69

How many copies of every gene are in each somatic cell?

Back 69

2 copies

Front 70

Alleles

Back 70

alternate versions of a gene

Front 71

Example of allele?

Back 71

yellow or green

Front 72

Pure breeding or homozygote

Back 72

two identical alleles for a trait

ex: AA, aa

Front 73

Hybrid or heterozygote

Back 73

two different alleles

Front 74

Dominant allele

Back 74

Allele that is expressed in a heterozygote

Aa= yellow

Front 75

Recessive allele

Back 75

Allele that is masked in a heterozygote

Front 76

Genotype

Back 76

allelic composition of a gene

Aa, AA, aa

Front 77

Phenotype

Back 77

expression of a trait

yellow or green

Front 78

Tester

Back 78

homozygous recessive for all genes being examined

Front 79

Homozygote x Homozygote

genotypes of offspring?
phenotypes of offsprint?

Back 79

genotypes: all the same
phenotypes: all the same

Front 80

Monohybrid x Monohybrid

genotypic ratio?
phenotypic ratio?

Back 80

genotypic ratio: 1:2:1

phenotypic ratio: 3:1

Front 81

Monohybrid x tester

genotypic ratio:
phenotypic ratio:

Back 81

genotypic ratio: 1:1
phenotypic ratio: 1:1

Front 82

Mendels principle of independent assortment

Back 82

As meiosis ends, genes on pairs of homologous chromosomes have been sorted out for distribution into one gamete or another, independently of gene pairs of other chromosomes.

Front 83

Dihybrid x dihybrid

phenotypic ratio?

Back 83

9:3:3:1

9: both dominant
3: one dom, one recessive
3: one recess, one dominant
1: both recessive

Front 84

Dihybrid x tester

phenotypic ratio?

Back 84

1:1:1:1

Front 85

3 things Mendel did not observe

Back 85

1) multiple alleles
2) codominance
3) incomplete inheritance

Front 86

Multiple alleles

Back 86

3 or more alleles for one gene in a population

A1, A2, A3

example: red blood cells
Ia (rbcs make a antigen on surface), Ib(rbcs make b antigen on surface), i (rbcs make no antigen)

Front 87

Codominance

Back 87

They are both expressed in a heterozygote

ex:Ia and Ib

Front 88

Incomplete Dominance

Back 88

One allele of a pair is not fully dominant over the other in a heterozygote, so an "intermediate" phenotype is observed

ex: A (red) and a (white)
Aa (pink)

Phenotypic ratio and genotypic ratio are the same

Front 89

Rule of Multiplication (Product Rule)

Back 89

The probability of a compound event is the product of separate probabilities

(.5x.5x.5....)

Front 90

Rare Autosomal Dominant Disorders

Back 90

Need one dominant allele to have the disease. (A/a=disease, A/A death rarely seen a/a normal)

Affected individuals usually have one affected parents

Doesnt skip generations

Front 91

Examples of Rare Autosomal Dominant Disorders (2)

Back 91

1) achondroplasia- dwarfism
2) huntington's disease--neurological

Front 92

Rare Autosomal Recessive Disorders

Back 92

Needs two recessive alleles to have the disease (A/A normal, A/a normal carrier, a/a has disease)

Affected individuals usually have unaffected parents

Skips generations

Inbreeding increases frequency in a population

Front 93

What increases Rare Autosomal Recessive Disorders in a population?

Back 93

inbreeding

Front 94

Examples of Rare Autsomal Recessive Disorders (3)

Back 94

1) cystic fibrosis
2) tay sachs disease
3) sickle cell disease

Front 95

Cystic fibrosis

Back 95

-1 in 20 carriers
-most common genetic disease in Caucasians
-it is thick mucus in lungs and respiratory tract, chronic lung infections, malnutrition because of missing pancreatic enzymes, infertility in males, salty babies

Front 96

Tay Sachs Disease

Back 96

-neurological
-jewish child dead by 3

Front 97

Sickle Cell Disease

Back 97

-1 in 12 carriers
- defect with hemoglobin
-most common genetic disease associated with individuals of African descent

Front 98

Examples of some common autosomal single gene Traits (4)

Back 98

1) feckles, no freckles
2) widows peak, straight hairline
3) free earlobes, attached earlobes
4) left thumb, right thumb

these are not rare, and they do not affect survival or reproduction

Front 99

Rare X-linked recessive disorders

Back 99

mutated gene is located on the x chromosome

only one recessive allele is needed in males to have disease

females would need two copies

Front 100

Rare X-linked recessive disorders: usually have affected or unaffected parents?

Back 100

unaffected parents

Front 101

What increases Rare X linked recessive disorders?

Back 101

inbreeding in population

Front 102

Examples of rare x-linked recessive disorders (3)

Back 102

1) red-green colorblindness
2) hemophilia- bleeding disorder
3) muscular dystrophies- muscular degenerative diseases

Front 103

Anueuploidy

Back 103

Abnormal number of chromosomes in humans

(2n + 1) 47 chromsomes

Front 104

What causes Anueploidy?

Back 104

errors in meiosis; nondisjunction in meiosis I and meisis II

Front 105

Non disjunction in meiosis I

Back 105

Homologs dont seperate; all aneuploid (n+1) (n+1) (n-1) (n-1)

Front 106

Non disjunction in meiosis II

Back 106

Sister chromatids dont separate in one of the two cells; 1/2 aneupoloid

(n) (n) (n+1) (n-1)

Front 107

Aneuploidy in autosomes

Back 107

monosomy
trisomy

Front 108

Monosomy

Back 108

Losing one autosome, not compatible with life (human)

Front 109

Trisomy

Back 109

Gain one autosome

Front 110

Trisomy 13,18,21

Back 110

down syndrome, only ones that make it through development to birth

Front 111

What increases the risk of Aneuploidy in autsomes?

Back 111

Woman ages because her eggs are arrested in prophase I, non-disjunction becomes more common

Front 112

Aneuploidy in sex chromosomes

Back 112

gain or loss of sex chromosome

Front 113

Examples of aneuploidy in sex chromosomes (4)

Back 113

XXY
XYY
XO
XXX

Front 114

XXY

Back 114

Trisomy; Kleninfelters syndrome, feminized male, tall and thin, immature breasts, sterile

Front 115

XO

Back 115

"Turners syndrome"
monosomy of the x
webbed neck
short
sterile (female)

Front 116

XXX

Back 116

normal fertile females

Front 117

Fred Griffith

Back 117

investigated the nature of genetic material mouse experiment with s & r stains of streptococcous

Front 118

What was the consensus at the time on genetic material?

Back 118

That eukaryote chromsomes carry genetic material and it consists of DNA and proteins

Genetic material was either DNA or proteins

Front 119

Oswald Avery, Colin MacLeod, Maclyn McCarty

Back 119

Test nature of genetic materials, DNA-inheritable, similar experiment with mice

Use DNase and protease to determine