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Biology > Bio Ch 8-9 Continued > Flashcards

Bio Ch 8-9 Continued Flashcards

(86 cards)

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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
Meiosis takes place in the gonads
Females: in the ovaries Males: in the testes
26
Each individual gets
1 maternal and 1 paternal copy of each homologous chromosome
27
Homologous
have the same genes (but the alleles can be different) - (same size, same spot)
28
Karyotype
pic of a person's chromosomes
29
need 1 member of chromosomes for every pair
can get more of maternal or paternal - why you look more like mother or father
30
Prophase 1
homologous chromosomes are near one another - allows them to cross over; switch pieces Further increases genetic variation - want genetic variation from an evolutionary standpoint
31
Metaphase 1
homologous chromosomes line up next to each other in the center 23 pairs in humans
32
Anaphase 1
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
33
Telophase 1 + Cytokinesis
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
34
Division 2 of Meiosis
DNA doesn't replicate
35
Prophase 2
-Chromosomes in daughter cells condense -Spindle forms -Nuclear membrane disintegrates again
36
Metaphase 2
sister chromatid pairs line up at the center of the cell
37
Anaphase 2
Sister chromatids are pulled apart by spindle fibers to opposite cell poles
38
Telophase 2 and Cytokinesis
-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
Summary of Meiosis 1 and 2
Meiosis 1: 1st division, homologous pairs separate Meiosis 2: 2nd division, sister chromatids separate
40
Sex Determination
male determines sex: depends on what sex chromosome is in that sperm cell -females lack Y chromosome and live normal happy lives
41
No information on the Y chromosome is necessary for development of a functioning human
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
Chromosomal disorders can be detected before birth
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
Downs Syndrome
another chromosome on the 21st pair have 47 chromosomes another name for Downs Syndrome is Trisomy 21
44
Ways of detecting Downs Syndrome
Amniocentesis - sample taken from amniotic fluid surrounding fetus Chronionic villus sampling (CVS) - cells obtained from placenta
45
Nondisjunction
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
problems associated with reproduction increase
as women age
47
Cases of Nondisjunction
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
Genetics: Fish odor syndrome
Individual smells like rotting fish - inherited disorder
49
Humans have 23 pairs of chromosomes
1 maternal copy and 1 paternal copy
50
Offspring inherits genes from parents (Fish Odor Syndrome)
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
Some traits are controlled by
a single gene
52
Heredity
the passing of characteristics from parent to offspring through their genes
53
Selective Breeding
can choose certain things -ex: sperm donor/ egg donor -ex: GMOs -ex: animals
54
Single-Gene Traits
some traits determined by instructions an organism caries on 1 gene -Most human characteristics are influenced by multiple genes and the environment
55
Why Mendel's experiment was successful
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
True Breeding (Pure, homozygous)
offspring would always produce the same characteristics --Mendel had to make sure plants were true breeding -- he crossed over plants
57
Mendel Studied
what is the likelihood of having a certain trait - collected lots of data
58
Dominent Trait
masks or hides recessive if it's present - sometimes recessive is more popular because of evolution
59
After Mendel crossed over flowers
second generation had white flowers reappear
60
PP,pp
PP= homozygous purple pp= homozygous white genotype true breeders ---only use 1 letter for a trait -------represents dominent vs recessive
61
result of crossing over PP true breeder and pp true breeder, 2nd generation
heterozygous; hybrid flowers - both dominant and recessive trait present - Pp; purple flowers there were 100% purple flowers- phenotype 100% Pp- genotype
62
He then crossed two Pp flowers
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
can't tell from the phenotype whether the trait was dominant
can tell by phenotype if the trait was recessive
64
Mendel's Law of Segregation
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
Steps of Mendel's Law of Segregation
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
Probability
chances don't increase - it's always a 25% every time the giraffes reproduce for the offspring to be albino
67
Test-Cross
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
Pedigree
type of test-cross - maybe used to determine whether a trait is dominant or recessive, sex-linked or autosomal
69
How to determine a genotype using a pedigree?
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
sex-linked
on sex chromosomes (X)
71
Incomplete Dominance
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
Codominance
a heterozygous individual shows features of both homozygotes - both alleles showing up equally --ex: blood type; type AB blood
73
Blood Type
-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
Antigens
are like signposts in the body's immune system; telling whether a cell belongs in the body
75
Antibodies
immune system molecules in the bloodstream that attacks foreign invaders
76
What blood type is the universal blood donor?
O because it there's nothing foreign being placed with any blood type
77
What blood type is the universal recipient?
AB because it can be paired with A, B, AB, or O
78
Polygenic
traits are influenced by many different genes - continuously varying
79
Additive Effect
when the effects of multiple genes contribute to the ultimate phenotype
80
Pleiotropy
occurs when 1 gene influences multiple, unrelated genes
81
Colorblindness
a sex linked trait/ X linked trait - only carried on the X chromosome explain % of colorblind child, % of colorblind female, % of colorblind male
82
Environmental Effects
genes interact with the environment to produce physical characteristics
83
Phenylketonuria (PKU)
a mutated version of a gene produces a malfunctioning enzyme that is unable to convert phenylalanine into tyrosine
84
Dihybrid
an individual who's heterozygous for 2 traits ---mating 2 such individuals is a dihybrid cross
85
Mendel's Law of Individual Assortment
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
Epigenics
impact of environment on genes Agouti gene- yellow mouse: coat color indicator, Methyl turns off gene

Biology (4 decks)

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