Biology 1 Chapter 13 (Lecture) Flashcards
(70 cards)
1
Q
Heredity
A
The transmission of traits from one generation to the next.
2
Q
Genetics
A
The scientific study of heredity and hereditary variation.
3
Q
Genes
A
Discrete units of hereditary info consisting of a specific nucleotide sequences in DNA.
4
Q
What are Gametes?
A
Sperm & Eggs
5
Q
DNA is packaged into…
A
…Chromosomes. Each chromosomes consists of a single long DNA molecule coiled in association with various protein.
6
Q
Locus
A
A gene’s specific location along the length of a chromosome.
7
Q
Asexual Reproduction
A
- Genetical identical offspring
- Produced by mitosis
- clone
- 1 parent
8
Q
Sexual Reproduction
A
- 2 parents
- Offsprings are identical
9
Q
Life Cycle
A
The generation to generation sequence of stages in the reproductive history of an organism from conception to production of its own offspring.
10
Q
Karyotype
A
A display of condensed chromosomes arranged in pairs.
11
Q
A pair of chromosomes have:
A
- Same length
- Same centromere position
- Same staining pattern
- Are called homologous chromosomes or homologs
12
Q
Sex Chromosomes: Female
A
XX
13
Q
Sex Chromosomes: Male
A
XY
14
Q
Non sex chromosomes are called:
A
Autosomes
15
Q
The “n” number
A
The number of chromsomes in a single set (A set is always haploid)
16
Q
Diploid Cell
A
Any cell with 2 chromosome sets and is referred to as 2n.
17
Q
Human diploid number
A
46
2n=46
18
Q
Human haploid number
A
23
(22 autosomes + single sex chromosome)
19
Q
Fertilization
A
The union of gametes
20
Q
Zygote
A
The fertilized egg and is 2n
21
Q
The only cells not produced by mitosis are…
A
… The gametes and they are formed by meiosis
22
Q
Preceded by replication of chromosomes. (Mitosis)
A
Yes
23
Q
Preceded by replication of chromosomes. (Meiosis)
A
Yes for Meiosis I
No for Meiosis II
24
Q
Number of cell divisions. (Mitosis)
A
1
25
Number of cell divisions. (Meiosis)
2
26
Results in. (Mitosis)
2 daughter cells (Identical)
27
Results in. (Meiosis)
4 daughter cells (Not identical)
28
Number of chromosomes in daughter cells as compared to parent cell. (Mitosis)
Same
29
Number of chromosomes in daughter cells as compared to parent cell. (Meiosis)
Half
30
Sister chromatids make up one replicated...
... Chromosome
31
The two chromosomes of a homologous pair are...
... Individual chromosomes that were inherited from different parents.
32
3 Events Unique to Meiosis Occur During Meiosis I:
1. Synapsis & Crossing Over
2. Homologs on the metaphase plate
3. Separation of homologs
33
Synapsis
Homologous chromosomes loosely pair up, aligned by genes.
34
Crossing Over
* ***_Nonsister_*** chromatids exchange DNA segments
* 1-2 per pair
* **_Prophase I_**
35
Meiosis is often called reduction division because it...
... Halves the number of chromsomes.
36
Origins of Genetic Variation Among Offspring:
* Independent Assortment of Chromosomes (Metaphase I)
* Crossing Over (Prophase I)
* Random Fertilization
37
Independent Assortment of Chromosomes
In humans there are more than 8 million (223) possible combos of chromosomes.
38
What is a genome?
The complete complement of an organism's gene
39
What is incorrect about genes?
Under normal circumstances, each chromosome contains precisely one gene.
40
Asexual reproduction and sexual reproduction are different in that
A) aswexual reproduction only requires mitosis, whereas sexual reproduction always involves meiosis
B) asexual reproduction produces offsprings that are genetically identical to the parent, whereas sexual reproduction gives rise to genetically distinct offspring
C) Asexual reproduction involves a single parent, whereas sexual reproduction involves two
D) individuals reproducing asexually transmit 100% of their genes to their progeny, whereas individuals reproducing sexually only transmit 50%
E) All of the above
E
41
How do the two members of a pair of homologous chromosomes differ from each other?
The precise sequence of the DNA within each of the chromosomes.
42
What is a karyotype?
A display of every pair of homologs within a cell, organized according to size and shape.
43
The human X and Y chromosomes are
Called "sex chromosomes" because they determine an individual's sex
44
If the liver cells of an animal have 24 chromosomes, how many chromosomes do its sperm cells have?
12
45
What is true of a species that has a chromosome number 2n=16?
there are 8 homologous pairs
46
At sexual maturity, ovaries and testes produce diploid gametes by meiosis. (T or F)
False
47
In animals, meiosis results in gametes, and fertilization results in
zygotes
48
In animals, somatic cells are produced by mitosis and ____ are produced by meiosis
Gametes
49
After telophase I of meiosis, the chromosomal makeup of each daughter cell is
haploid, and the chromosomes are composed of two chromatids.
50
What belongs with the words synapsis, tetrads, and chiasmata?
Crossing Over
51
Tetrads of chromosomes are aligned at the center of the cell; independent assortment soon follows.
Metaphase I
52
Synapsis of homologous pairs occurs; crossing over may occur.
Prophase I
53
Centromeres of sister chromatids uncouple and chromatids separate.
Anaphase II
54
What happens at the conclusion of Meiosis I?
Homologous chromosomes are separated
55
What is the result of meiosis?
4 haploid cells
56
Crossing over occurs during which phase of meiosis?
Prophase I
57
A cell divides to produce two daughter cells that are genetically identical.
True for mitosis only
58
Homologous chromosomes synapse and crossing over occurs.
True for Meiosis I only
59
Centromeres uncouple and chromatids are separated from each other.
True for Mitosis and meiosis II
60
Independent assortment of chromosomes occurs.
True for meiosis only
61
The process is preceded by replication of the DNA
True for Mitosis and meiosis I
62
You have in your possession a microscope slide with meiotic cells on it and a light microscope. What would you look for if you wanted to identify meaphase I cells on the slide?
Tetrads lined up at the center of the cell
63
When comparing prophase I of meiosis with prophase of mitosis, what occurs only in meiosis?
Tetrads form.
64
What occurs in meiosis but not in mitosis?
Synapsis and Alignment of tetrads at the metaphase plate
65
How does the sexual life cycle increase the genetic variations in a species?
By allowing crossing over, random fertilization, and independent assortment of chromosomes
66
For a species with a haploid number of 23 chromosomes, how many different combos of maternal and paternal chromosomes are possible for the gametes?
about 8 million
67
For a species with a diploid number of 10 chromosomes, how many different combos pf maternal and paternal chromosomes are possible for the gametes?
32 (25)
68
Independent assortment of chromosomes is a result of
The random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I
69
When pairs of homolgous chromosomes separate during anaphase I
The sister chromatids remaon linked to one another
70
What is incorrect about Crossing Over?
Crossing over plays a role in both sexual and asexual reproduction.
