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Biology > Bio Ch 8-9 Continued > Flashcards

Bio Ch 8-9 Continued Flashcards

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1
Q

1st Step in DNA Replication

A

Unwinding and Seperation
-DNA Helicase unwinds DNA molecule
-then seperates

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2
Q

2nd Step in DNA Replication

A

Reconstruction and Elongation
- Enzyme connects the appropriate nucleotides to the growing new strand
-Nucleotides are added to the end of the growing new strands; DNA Polymerase helps bring in nucleotides

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3
Q

DNA Complementary

A

Base strand always has a complementary strand
- maces it possible to reconstruct complementary strand (follows the base pairing rules)

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4
Q

Errors can occur in DNA Replication

A

mutated gene has an altered protein
ex: Sickle Cell Trait
- can be good
- normal red blood cells and sickle red blood cells
- 1 normal and 1 sickle cell gene
- protects against malaria

2 sickle cell genes is bad- have Sickle Cell Anemia

Usually not good when DNA Replication goes wrong

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5
Q

Mitosis

A

-Occurs in body cells/somatic cells
-Need it for growing and development
-Need it for repairing (injury/cells)
-All somatic cells go under Mitosis
-Some go under Mitosis longer than others; depends on the kind of cell
- Apoptosis: cell suicide

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6
Q

Before Mitosis Begins

A
  1. Chromosomes replicate (DNA is copied) (chromosomes are made up of DNA)
    - sister chromatids connected by a centromere= 1 chromosome
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7
Q

As Mitosis Begins

A

-Spindle forms
-Spindle fibers attach to centromeres and pull sister chromatids to the center of the cell

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8
Q

How many chromosomes in a human?

A

46 replicated chromosomes in human body

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9
Q

4 Steps of Mitosis

A

Prophase
Metaphase
Anaphase
Telophase

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10
Q

Mitosis: Prophase

A

-Nuclear membrane breaks down
-Sister chromatids condense
-Spindle forms from cytoskeleton

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11
Q

Metaphase

A

Sister chromatids line up at the center of the cell

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12
Q

Anaphase

A

sister chromatid pairs are pulled apart by the spindle fibers to opposite ends

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13
Q

Telophase

A

-Chromosomes begin to uncoil
-Nuclear membrane reassembles
-Cytokinesis starts and the cell begins to pinch into 2

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14
Q

Cytokinesis for Mitosis

A

Cytoplasm is divided into the 2 daughter cells; genetically identical

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15
Q

Cancer Cells

A

ignore cell cycle and signals
1. Lose contact inhibition; continue to grow
2. Divide (grow) indefinitely; telomeres are ignored

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16
Q

Benign Tumors

A

-not harmful
-Masses of normal cells
-can become malignant over time
-can be removed safely

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17
Q

Malignant Tumors

A

Metastasis: shed and spread cancer cells elsewhere in the body

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18
Q

Meiosis

A

make egg and sperm cells; gametes
Sexual reproduction- fertilization

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19
Q

Mitosis produces

A

2 daughter cells with 46 diploid cells

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20
Q

haploid

A

half the chromosome number

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21
Q

Meiosis process

A

Starts with 1 diploid parent cell
then produces 2 haploid cells
then those haploid cells each produce 2 haploid cells
- 4 haploid cells in total: one gets chosen at random to become a person
- haploid cells aren’t genetically identical; why siblings don’t look exactly like one another

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22
Q

Sperm and egg combine in fertilization to get

A

46 chromosomes

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23
Q

Fertilization

A

2 haploid cells merge to create a diploid person

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24
Q

2 Outcomes of Meiosis

A

-reduces the amount of genetic material in gametes
- produces gametes that differ from one another with respect to the combination of alleles they carry

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25
Q

Meiosis takes place in the gonads

A

Females: in the ovaries
Males: in the testes

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26
Q

Each individual gets

A

1 maternal and 1 paternal copy of each homologous chromosome

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27
Q

Homologous

A

have the same genes (but the alleles can be different)
- (same size, same spot)

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28
Q

Karyotype

A

pic of a person’s chromosomes

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29
Q

need 1 member of chromosomes for every pair

A

can get more of maternal or paternal
- why you look more like mother or father

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30
Q

Prophase 1

A

homologous chromosomes are near one another
- allows them to cross over; switch pieces

Further increases genetic variation
- want genetic variation from an evolutionary standpoint

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31
Q

Metaphase 1

A

homologous chromosomes line up next to each other in the center
23 pairs in humans

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32
Q

Anaphase 1

A

spindle fibers pull homologous chromosomes apart
- this is when the chromosome number is reduced to half
- end up with 2 daughter cells with 23 chromosomes

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33
Q

Telophase 1 + Cytokinesis

A

daughter cells are Not identical
- Sister chromatids arrive at the cell poles and the nuclear membrane reassembles around them
- the cell pinches into 2 daughter cells
- chromosomes may unwind slightly

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34
Q

Division 2 of Meiosis

A

DNA doesn’t replicate

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35
Q

Prophase 2

A

-Chromosomes in daughter cells condense
-Spindle forms
-Nuclear membrane disintegrates again

36
Q

Metaphase 2

A

sister chromatid pairs line up at the center of the cell

37
Q

Anaphase 2

A

Sister chromatids are pulled apart by spindle fibers to opposite cell poles

38
Q

Telophase 2 and Cytokinesis

A

-The nuclear membrane reassembles around the chromosomes
-The 2 daughter cells pinch into 4 haploid cells
—- genetic variation between the 4 haploid cells
—-sperm fertilizes random egg

39
Q

Summary of Meiosis 1 and 2

A

Meiosis 1: 1st division, homologous pairs separate
Meiosis 2: 2nd division, sister chromatids separate

40
Q

Sex Determination

A

male determines sex: depends on what sex chromosome is in that sperm cell
-females lack Y chromosome and live normal happy lives

41
Q

No information on the Y chromosome is necessary for development of a functioning human

A

lots of info on the X chromosome that os necessary
-ppl who only get 1 X chromosome= baby still fully develops (with a genetic disorder)
—not possible to have baby with 1 Y no X

42
Q

Chromosomal disorders can be detected before birth

A

After age 35 in mother incidence for having a child with Downs Syndrome increases
- doesn’t mean the woman will
- greater population of women who are younger having children
— therefor more incidences of having children with Downs Syndrome from women younger than 35

43
Q

Downs Syndrome

A

another chromosome on the 21st pair
have 47 chromosomes
another name for Downs Syndrome is Trisomy 21

44
Q

Ways of detecting Downs Syndrome

A

Amniocentesis
- sample taken from amniotic fluid surrounding fetus

Chronionic villus sampling (CVS)
- cells obtained from placenta

45
Q

Nondisjunction

A

unequal distribution of chromosomes during cell division
- cases of trisomy tend to involve only chromosomes with the fewest genes
—chromosomes 13, 15, 18, 21, and 22
—-trisomy 18- child dies

46
Q

problems associated with reproduction increase

A

as women age

47
Q

Cases of Nondisjunction

A

Turners Syndrome (Female)
- child with 1 X chromosome
- has 45 chromosomes total
-short height
- webbed skin
- sterile
- learning difficulties

Klinefelters Syndrome (Male)
XXY
- has 47 chromosomes total
- lower testosterone levels than average; infertile
- development of some female features
- long limbs
- taller than average
2 possible ways this could have happened
1. female had 2 X’s by nondisjunction
2. egg cell normal but sperm cell had extra chromosome by nondisjunction

XYY Male
- taller than average
- moderate to severe acne
- intelligence slightly lower
- sometimes called supermales

XXX Female
- may be sterile
- no obvious physical or cognitive problems
- sometimes called metafemales

48
Q

Genetics: Fish odor syndrome

A

Individual smells like rotting fish
- inherited disorder

49
Q

Humans have 23 pairs of chromosomes

A

1 maternal copy and 1 paternal copy

50
Q

Offspring inherits genes from parents
(Fish Odor Syndrome)

A

must inherit both defective genes (paternal gene and maternal gene) for fish odor syndrome
- parents can be carriers (wouldn’t have the consequences of it)

51
Q

Some traits are controlled by

A

a single gene

52
Q

Heredity

A

the passing of characteristics from parent to offspring through their genes

53
Q

Selective Breeding

A

can choose certain things
-ex: sperm donor/ egg donor
-ex: GMOs
-ex: animals

54
Q

Single-Gene Traits

A

some traits determined by instructions an organism caries on 1 gene
-Most human characteristics are influenced by multiple genes and the environment

55
Q

Why Mendel’s experiment was successful

A
  1. The organisms were ideal to study
  2. Numerous easily categorized traits with 2 variants each
  3. Distinct population established
    —–he looked at 7 characteristics
    purple, white (flower)
    round, wrinkled (pea plant)
    yellow, green (pea plant)
56
Q

True Breeding (Pure, homozygous)

A

offspring would always produce the same characteristics
–Mendel had to make sure plants were true breeding
– he crossed over plants

57
Q

Mendel Studied

A

what is the likelihood of having a certain trait
- collected lots of data

58
Q

Dominent Trait

A

masks or hides recessive if it’s present
- sometimes recessive is more popular because of evolution

59
Q

After Mendel crossed over flowers

A

second generation had white flowers reappear

60
Q

PP,pp

A

PP= homozygous purple
pp= homozygous white
genotype
true breeders
—only use 1 letter for a trait
——-represents dominent vs recessive

61
Q

result of crossing over PP true breeder and pp true breeder, 2nd generation

A

heterozygous; hybrid flowers
- both dominant and recessive trait present
- Pp; purple flowers
there were 100% purple flowers- phenotype
100% Pp- genotype

62
Q

He then crossed two Pp flowers

A

the next generation
- Phenotype: for every 3 purple flowers, 1 white flower
–75%Purple, 25% white
—3:1
- Genotype: 25% PP, 50% Pp, 25%pp
1:2:1

63
Q

can’t tell from the phenotype whether the trait was dominant

A

can tell by phenotype if the trait was recessive

64
Q

Mendel’s Law of Segregation

A

only 1 of 2 alleles for a gene is passed to a gamete. Offspring receive from each parent 1 allele for each gene at fertilization

65
Q

Steps of Mendel’s Law of Segregation

A
  1. each parent puts into every sperm or egg it makes a single set of instructions for building the trait (they combine at fertilization)-> occurs by meiosis
  2. offspring receive 2 copies of the instructions for any trait
  3. the trait observed in an individual depends on the 2 copies of the gene it inherits from it’s parents

–> only 1 of the 2 alleles gets given from parent
Homozygous recessive
Heterozygous
Homozygous dominent

66
Q

Probability

A

chances don’t increase
- it’s always a 25% every time the giraffes reproduce for the offspring to be albino

67
Q

Test-Cross

A

used when you don’t know the genotype- reveals the genotype
- enables us to figure out which alleles an individual carries
-trait may show up and was being masked

68
Q

Pedigree

A

type of test-cross
- maybe used to determine whether a trait is dominant or recessive, sex-linked or autosomal

69
Q

How to determine a genotype using a pedigree?

A

look at the children to se whether it’s dominant, recessive, or heterozygous
- (sometimes you can’t tell)
Can determine if someone is a carrier

70
Q

sex-linked

A

on sex chromosomes (X)

71
Q

Incomplete Dominance

A

the phenotype of a heterozygote is intermediate between the phenotypes of 2 homozygotes
- flower example: traits are blending together to create a whole new phenotype
–100% pink

72
Q

Codominance

A

a heterozygous individual shows features of both homozygotes
- both alleles showing up equally
–ex: blood type; type AB blood

73
Q

Blood Type

A

-3 alleles for blood
–A, B, none (gene with nothing on it)
-6 possible genotypes: IAIA, IAi, IBIB, IBi, IAIB, and ii
-4 phenotypes: A, B, AB, or O

74
Q

Antigens

A

are like signposts in the body’s immune system; telling whether a cell belongs in the body

75
Q

Antibodies

A

immune system molecules in the bloodstream that attacks foreign invaders

76
Q

What blood type is the universal blood donor?

A

O because it there’s nothing foreign being placed with any blood type

77
Q

What blood type is the universal recipient?

A

AB because it can be paired with A, B, AB, or O

78
Q

Polygenic

A

traits are influenced by many different genes
- continuously varying

79
Q

Additive Effect

A

when the effects of multiple genes contribute to the ultimate phenotype

80
Q

Pleiotropy

A

occurs when 1 gene influences multiple, unrelated genes

81
Q

Colorblindness

A

a sex linked trait/ X linked trait
- only carried on the X chromosome
explain % of colorblind child, % of colorblind female, % of colorblind male

82
Q

Environmental Effects

A

genes interact with the environment to produce physical characteristics

83
Q

Phenylketonuria (PKU)

A

a mutated version of a gene produces a malfunctioning enzyme that is unable to convert phenylalanine into tyrosine

84
Q

Dihybrid

A

an individual who’s heterozygous for 2 traits
—mating 2 such individuals is a dihybrid cross

85
Q

Mendel’s Law of Individual Assortment

A

When neither of 2 traits influences the inheritance of the other trait, it is said that they’re inherited independently of each other
-most are passed on independently

86
Q

Epigenics

A

impact of environment on genes
Agouti gene- yellow mouse: coat color indicator, Methyl turns off gene

Biology (4 decks)

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