BSCI 1511 Lecture Notes - Lecture 4: Sister Chromatids, Homologous Chromosome, Somatic Cell

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burgundyhound116

18 Jan 2019

School

Vanderbilt University

Department

Biological Sciences

Course

BSCI 1511

Professor

Abbot Patrick, Julian Hillyer

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Document Summary

Meiosis creates genetic diversity within individuals, who produce gametes, so when they reproduce, they pass on all that genetic diversity to their offspring. Offspring acquire genes from parents from inheriting chromosomes. Meiosis reduces the number of chromosome sets from diploid to haploid. 4 haploid cells arising from meiosis are genetically different. 3 main sources of genetic variation: independent assortment (from meiosis), crossing over (from meiosis), random fertilization. Genes are inherited by maximum 2 individuals: mom and dad. Somatic cells contain 23 pairs of chromosomes (46 total)- called diploid 2n. In meiosis, germ cells (2n) divide and result in gametes with only 1 set of chromosomes- called haploid n. Union of 2 gametes=diploid zygote with 1 set of chromosomes from each gamete from each parent (one from sperm, one from egg) Each species has a characteristic diploid and haploid #= humans (46, 23) Karyotype- display of chromosome pairs of a cell arranged by size and shape.

Related Questions

1. How does meiosis generate genetic diversity?

a) crossing over

b) random alignment at metaphase I

c) synapsis

d) both crossing over and random alignment at metaphase I

2. What would happen if crossing over occurred between sister chromatids?

a) Genetic diversity would decrease due to the loss of gene combinations.

b) Genetic diversity would increase due to the addition of gene combinations.

c) Gene rearrangement would lead to changes in gene expression.

d) Nothing would happen becasue sister chromatids are genetically identical or nearly identical.

3. Animals that sexually reproduce are _____ and produce _____ gametes. (haploid, diploid; haploid, haploid; diploid, diploid; diploid, haploid)

4. The F1 generation of a cross between two individuals, one that is homozygous dominant for a trait and the other that is homozygous recessive for the trait, will yield progeny with the same phenotype. (true or false)

5. Homologous chromosomes separate from each other in:

a) mitosis

b) meiosis I

c) meiosis II

d) They never separate from each other during any form of cell division

chocolatealpaca651

M2A1 Worksheet: Mitosis and Meiosis

A dog is a diploid organisms and has 39 pairs of chromosomes (2n = 78), where n = 39 chromosomes from each parent. Use this example to answer the following question regarding chromosomal number.

INTERPHASE

How many chromosomes are present in the somatic cell?

What do they look like?

What are they âdoingâ in G1 of this phase?

What is happening in the S phase?

What is happening in the G2 phase?

What follows G2 phase in a somatic cell?

What follows G2 phase in a gamete cell?

MITOSIS

Number of chromosomes in the parent cell.

Number of chromatids in the parent cell.

Number of chromosomes in the daughter cell.

Number of chromatids in the daughter cell.

How many daughter cells are produced?

Are the daughter cells haploid or diploid?

How many cell divisions take place?

In what type of cell does this division occur?

Meiosis 1:

Number of chromosomes in the parent cell.

Number of chromatids in the parent cell.

Number of chromosomes in each Meiosis I daughter cell.

Number of chromatids in each Meiosis I daughter cell.

Are the daughter cells haploid or diploid at the end of Meiosis 1?

Meiosis II:

Number of chromosomes in the âparentâ cell (which is a daughter cell from Meiosis I).

Number of chromatids in the âparentâ cell.

Number of chromosomes in each Meiosis II daughter cell.

Number of chromatids in each Meiosis II daughter cell.

Are the daughter cells haploid or diploid at the end of Meiosis II?

Which phase or phases of Meiosis account for the genetic variability among the daughter cells? Howâ¦ what happens in this phase to create the diversity?

Comparing Mitosis and Meiosisâ¦..

How many daughter cells result from Mitosis? Are they diploid or haploid?

How many daughter cells result from Meiosis? Are they diploid or Haploid?

Cell structures and function: Match each organelle to its function:

Organelle Function

Lysosome 1. Lipid synthesis

Rough ER 2. Houses DNA

Nucleus 3. Energy extraction

Smooth ER 4. Dismantles debris

Golgi apparatus 5. detoxification

Mitochondria 6. Protein synthesis

Peroxisome 7. Processes secretions

What is the function of checkpoint proteins in the cell cycle?

How can all of a personâs cells contain exactly the same genetic material, yet specialize as bone cells, nerve cells, muscle cells and connective tissues?

What are the 3 primary germ layers?

Briefly, in one or two sentences, distinguish between

a bacterial cell and a eukaryotic cell

interphase and mitosis

mitosis and apoptosis

an autosome and a sex chromosome

homologous pair of chromosomes and a sister chromatid

centromere and centriole

chromosome and chromatid

monozygotic and dizygotic twins

allele and gene

13. Meiosis differs from mitosis in that:
a. meiosis results in the production of two new cells, whilemitosis results in the production for four new
cells., b. meiosis is used for growth and repair, while mitosis isused for production of eggs and sperm., c.
cytokinesis can be unequal following meiosis, but is approximatelyequal following mitosis., d. meiosis
involves one cell division, while mitosis involves two celldivisions., e. meiosis results in the production of
diploid cells, while mitosis results in the production of haploidcells.
14. Bits of maternal and paternal chromosomes are exchanged betweenhomologous chromosomes during
synapsis of meiosis I. This process is called:
a. crossing over., b. random mating., c. random fertilization., d.random shuffling of parental
chromosomes.,
e. mutation.
15. The advantage of sexual reproduction over asexual reproductionis that:
a. all young are genetically identical to the parent., b. malesmust evolve a copulatory organ., c. genetic
variability in the population is increased., d. females must evolvea vagina., e. mates are not needed.
16. Many different types of information are used to constructphylogenetic trees. Which of the following types
of information is the most direct measure of evolutionaryrelatedness?
a. physiology, b. gene sequence data, c. the fossil record, d.information about the structure of ribosomes.,
e. information about the structure of enzymes
17. A species is:
a. a group of individuals that can interbreed under naturalconditions and produce fertile offspring., b.
denoted by both a genus and a species name., c. the onlybiologically defined taxon., d. a group of
organisms with a large number of traits in common., e. all of theabove.
18. The process of spermatogenesis results in:
A. 4 diploid sperm; B. 1 diploid sperm and 3 haploid polar bodies;C. 1 haploid sperm and 3 haploid
polar bodies; D. 4 haploid sperm
19. Which cell division process results in an unequal division ofthe cytoplasm?
A. Spermatogenesis; B. Testiculargenesis; C. Oogenesis; D. None ofthe above
20. Meiosis is the process by which:
A. 1 diploid cell becomes 4 haploid cells; B. 1 diploid cellbecomes 1 haploid cell and 3 haploid polar
bodies; C. 1 haploid cell becomes 4 diploid cells; D. Both A andB
21. The phase of mitosis where chromosomes line up at the equator(middle) of the cell is called:
A. Anaphase; B. Telophase; C. Interphase; D. Metaphase
22. Chromosome #6 from Mom and Chromosome #6 from Dad form achromosome pair called:
A. Sister Chromatids; B. Centromeres; C. Homologous Chromosomes; D.Spindle Apparatus

scarlethare433

BSCI 1511 Lecture Notes - Lecture 4: Sister Chromatids, Homologous Chromosome, Somatic Cell

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