Exam 3 Flashcards
1
Q
Diploid (2N)
A
Having 2 complete sets of chromosomes per cell
N=one complete set of chromosomes
2
Q
All somatic (body) cells, except for __ are diploid
A
Egg and sperm cells (sex cells)
3
Q
Haploid (N)
A
Having one set of chromosomes per cell
Only sex cells are haploid
4
Q
2 kinds of nuclear division
A
Mitosis
Meiosis
5
Q
Mitosis
A
Ordinary nuclear cell division for growth and repair
Occurs in somatic (body) cells
6
Q
Meiosis
A
Nuclear division
For producing sex cells
7
Q
Cytokinesis
A
Division of the cytoplasm and it’s contents
In plant cells, a cell plate forms that divides the cell into 2 daughter cells
In animal cells, the plasma membrane pinches inward
8
Q
Control of the cell cycle
A
Outside influences ex: growth hormone or other hormones
Adhesion to a solid surface: in order to divide, the cell must be able to push neighboring cells or some other solid surface
Contact inhibition: cells will stop dividing when they touch or contact neighboring cells
9
Q
Cancer
A
Uncontrolled mitosis
10
Q
Benign
A
Not life threatening (not cancerous) Cells are differentiated Encapsulated Uniform shape Do not metastasize
11
Q
Malignant
A
Can be life threatening (cancerous) Undifferentiated Not encapsulated Can metastasize Can have feeders, not uniform in shape
12
Q
3 things cell division accomplishes
A
Reproduction (single-celled organisms)
Growth, maintenance (repair), renewal (multicellular)
Maintenance of an adequate surface area to volume ratio
13
Q
Prokaryotic DNA (bacteria)
A
Consists of a single loop of DNA: located in the nucleoid region of cell
Undergo binary fission
14
Q
Eukaryotic DNA
A
Consists of larger chromosomes located in nucleus
15
Q
Binary fission
A
Mitosis without organelles inside Single prokaryotic cell DNA replicates Cell elongates and DNA loops separate Plasma membrane pinches in Produces 2 identical daughter cells
16
Q
DNA
A
Genetic material
17
Q
Chromatin
A
Loosely arranged form of DNA
Seen when cell is not dividing actively
18
Q
Chromosome
A
Condensed or compact version of DNA
19
Q
Chromatid
A
Half of a duplicated chromosome
20
Q
Centromere
A
Constructed region of the chromosome
Holds the sister chromatid together until division
21
Q
Concerning eukaryotes:
A
We can count the # of chromosomes in a species Humans (46) Chimpanzee (48) Dog (78) Potato (48)
22
Q
Mitosis
A
Interphase Prophase Metaphase Anaphase Telophase Produces two genetically identical daughter cells
23
Q
Interphase
A
Somatic cell containing chromatin
24
Q
Prophase
A
Nuclear membrane breaks down
Chromatin condensed into chromosomes
25
Late prophase
Chromosomes replicate
| Twice as much DNA in cell at this point
26
Metaphase
Chromosomes line up single file along the equator
27
Anaphase
Sister chromatids separate
28
Telophase
Nucleoplasm pinches in
29
Late telophase
Nuclear membrane reforms
30
Features of mitosis
One nuclear division
Sister chromatids separate
Diploid to diploid
Produces two genetically identical daughter cells
31
Asexual reproduction
Reproduction by binary fission or mitosis
Only requires one organism or cell
Daughter cells are clones of each other
32
Sexual reproduction
Reproduction through the fusion of male and female gametes (sex cells)
Requires two different organisms
Produces offspring that are genetically different/diverse
33
Meiosis
Nuclear division for the production of gametes (or eggs and sperm)
Only occurs in testes and ovaries
For plants: in the anthers of male part and ovary of female part
34
Homologous chromosomes
Matched pairs of chromosomes that carry genes for the same types of traits (even though the expression may be different)
One homolog comes from Dad, the other homolog comes from Mom
35
Meiosis (reduction division)
```
The number of chromosomes will be reduced by half
Interphase 1
Prophase 1
Metaphase 1
Anaphase 1
Telophase 1
prophase 2
Metaphase 2
Telophase 2
```
36
Interphase 1
Cell in ovaries or testes with chromatin
37
Prophase 1
Nuclear membrane breaks down
| Chromatin condenses into chromosomes
38
Late prophase 1
Chromosomes replicate
39
Metaphase 1
Homologous chromosomes pair up side by side along the equator
40
Metaphase 1
Homologous pairs separate
41
Telophase 1
Nucleoplasm pinches in
42
Late telophase 1 into prophase 2
2 haploid daughter cells
| No more DNA replication
43
Meiosis 2
| Metaphase 2
Chromosomes line up single file along equator
44
Telophase 2
Sister chromatids separate
| Produces 4 haploid daughter cells that are different from each other and from the parent cell
45
Crossing over
Occurs only in meiosis
Exchange of parts of chromosomes between homologous pairs (this is usually an equal exchange)
Significance: adds to genetic diversity
46
Features of meiosis
Two nuclear divisions to complete the process
Homologous pairs separate first, then the sister chromatids separate
Diploid to haploid
47
Spermatogenesis
Formation of sperm cells via meiosis
| 4 viable sperm cells are produced with each round of meiosis
48
Oogenesis
Formation of egg cells via meiosis
| Only one egg and 2 or 3 polar bodies are produced with each round of meiosis
49
Offspring of sexually reproducing organisms do not
Resemble either parent exactky because the offspring receive half of their genes from each parent
50
Blending hypothesis
Parents of contrasting appearance always produce offspring of intermediate appearance
(Incorrect)
This is actually incomplete dominance
51
Gregor Mendel
Austrian monk who taught science and was also trained in math
52
Mendel’s experiments
Worked with garden peas
Gathered data that could be analyzed mathematically
Peas are easy to grow, have a short generation time, produce lots of offspring, have easily discernible traits, can be crossbred
53
Particulate theory
Genes are inherited and passed on as discrete units (proposed by Mendel)
54
Allele
Alternative form of a gene
55
Dominant allele
Allele that masks the expression of another allele
| Trait that is shown
56
Recessive allele
Allele that has its expression masked in the presence of a dominant allele
57
Homozygous
Having two identical alleles for a given trait
| Same
58
Heterozygous
Having two different alleles for a given trait
59
Genotype
The actual alleles possessed by an organism
| Ex: TT, Tt, tt
60
Phenotype
The physical, chemical, or behavioral expression of alleles
Word description of the trait
What can be seen
Ex: tall, short, black, white, etc.
61
Reciprocal cross
Actually 2 crosses
62
Mendel’s Las of Segregation
Each organism contains 2 factors for each trait
These 2 factors separate during the formation of gametes so that each gamete contains only one factor for each trait
Upon fertilization, the new zygote (organism) has 2 factors for each trait (one from each parent)
63
Monohybrid cross
In a monohybrid cross when both parents are heterozygous for a completely dominant trait, we expect a 3:1 phenotypic ratio among the offspring
64
Genotypic ratio
Lists the proportions of each genotype obtained in a genetic cross
65
Phenotypic cross
Lists the proportions of each phenotype obtained in a genetic cross
66
Testcross
Cross between a dominant phenotype organism and a double recessive organism (always use a double recessive as a mate)
Reason to do a test cross is to figure out if the dominant phenotype organism is homozygous or heterozygous
If the dominant phenotype is homozygous, then ALL the offspring will show the dominant trait
If some or any offspring show the recessive trait, then we know the dominant phenotype parent is heterozygous
67
In a dihybrid cross With both parents heterozygous for both traits
A 9:3:3:1 phenotypic ratio is expected
68
Incomplete dominance
Pattern of inheritance in which the heterozygous shows a phenotype that is intermediate between the phenotypes if either of the homozygotes
The genotypic and phenotypic ratios are the same
69
Dihybrid cross
Genetic cross that involves 2 different genetic traits
70
Mendel’s rule of independent assortment
Alleles of different gene pairs assort (separate) independently of one another so that all possible combinations show up in gametes
FOIL
71
Genotypes
Always diploid
Genes come in pairs
Aa, AA
72
Gametes
Haploid
Single gene/allele
A
73
Codominance
Pattern of inheritance in which the heterozygotes shows both traits to their full extent
74
Multiple alleles (blood types)
There are more than 2 alternative alleles for a given genetic trait
Individuals only posses 2 alleles at a time
75
Rh factor
Separate protein that may be on the red blood cells
Rh+(dominant)
Rh-(recessive)
If the mom is Rh- and carries an Rh+ baby, then problems can arise
76
RhO gum
Artificial antibodies shot of antibodies given several times during pregnancy and right before birth
77
Genes
Code for proteins, enzymes, hormones
78
Phenotypes
Can be altered when an individual inherits an allele that codes for a defective gene product
79
Epistasis
Involves two different gene pairs
One pair of genes masks the expression of the other pair of genes
Ex: Albinism
80
In a dihybrid cross...
If a modification of the 9:3:3:1 phenotypic ratio is seen, then epistasis should be suspected
81
Polygenic inheritance
Refers to traits in which several to many pairs of alleles influence the trait
Ex: height, eye color, skin color
These are quantitative or additive traits
Each contributing allele adds a bit more to the expression of the trait
82
Most traits are not 100%
Genetic
| Both genes and environment work together to determine phenotype
83
Genes are located
On chromosomes, depending on the size of the chromosome, it may contain hundreds or thousands of genes
84
Autosomes
Any chromosome that is NOT a sex chromosome
| Humans have 22 pairs of autosomes (then a pair of sex chromosomes)
85
Sex chromosomes determine
```
The sex of the organism
Humans have one pair
Female: XX
Male: XY
(X chromosome is a lot larger than Y chromosome)
```
86
Karyotype
Arrangement of the chromosomes of an individual
The chromosomes are arranged from largest pair to smallest pair
The sex chromosomes are the 23rd pair
87
Karyotypes can show
Sex
Extra or missing chromosomes
Broken chromosomes
Translocations
88
Linkage group
Refers to all the genes located on a particular chromosome
The genes are linked to that chromosome
The closer 2 genes are on a given chromosome, the more tightly they are linked
The genes travel together and will not be separated as often by crossing over/recombination
89
Sex linked genes
Genes that are located on sex chromosomes
X-linked are on the X chromosome
Y-linked are on the Y chromosome
90
X linked traits
Red green color blindness
Hemophilia
Fragile x syndrome
All of these are recessive traits
91
Y linked traits
```
SRY gene (turns on the testosterone)
Hairy ears
```
92
Sex-influenced traits
Show up in both sexes, but they show up more often in one sex than the other
93
Mutation
Permanent change in the DNA of a gene or chromosome
| Mutations can be passed to offspring if they occur in gametes
94
Polyploidy
Having more than 2 complete sets of chromosomes per cell
95
Ploidy
Sets
96
Somy
Individual chromosomes
97
Monosomy
Having on copy of a particular chromosome (2N-1)
98
Trisomy
Having 3 copies of a particular chromosomes (2N+1)
99
The cause of monosomy and trisomy is
Nondisjunction
| The failure of chromosomes to separate properly during meiosis
100
Inversion
Piece of chromosome breaks loose, turns 180° and rejoins in the opposite/reverse direction
ABCDEFG
ABCDFEG
101
Translocation
Piece of one chromosome breaks off and attaches to a different (nonhomologous) chromosome
ABCDEFG
ABCDMN
102
Deletion
Piece of chromosome is lost
ABCDEFG
BCDEFG
