BIOLOGY 1A03 Lecture Notes - Lecture 5: Centrosome, Cytokinesis, Microtubule

27 views3 pages

erincat447

25 Mar 2018

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

doinhumolalala and 39849 others unlocked

BIOLOGY 1A03 Full Course Notes

Verified Note

9 documents

Document Summary

Gametes- passing gene to the next generation asexually reproducing organisms produce offspring that are exact genetic copies of themselves. The only cells in the human body that are not produced by mitosis are the gametes which are derived from specialized germ cells in the ovaries of females and the testes of males. Chromosomes are passed from parents to offspring in sexually reproducing organisms due to the formation of sex cells. With sexually reproducing organisms, the two parents give rise to offspring that have unique combinations of genes that are inherited from both parents. The female will produce one large egg cell (with a higher cytoplasmic volume) and 3 non- gametic polar bodies which serve a simple role to reduce the chromosomal content of the one egg gamete. If human gametes were produced by mitosis, they would be diploid and would give rise to offspring with double the chromosome number. This would lead to fatal effects in the offspring.

Related Questions

Match the terms to the definitions provided.

Question 1 options:

	gamete
	somatic cells
	zygote
	sexual reproduction

1.	Reproductive life cycle that involves an alternation between haploid and diploid cells
2.	A single cell with a diploid number of chromosomes resulting from the fusion of an egg and a sperm.
3.	Cells (egg or sperm) resulting from a meiotic division of germ-line cells
4.	The non-reproductive cells found in embryos and mature individuals

Question 2 (5 points)

Match the terms to the definitions provided.

Question 2 options:

	syngamy
	haploid
	meiosis
	diploid
	germ-line cells

1.	The cells that will eventually undergo meiosis to produce gametes.
2.	The number of chromosomes found in gametes (eggs or sperm).
3.	The process by which two haploid gametes fuse to form a new diploid cell.
4.	A specialized reduction division that produces cells with half the normal number of chromosomes.
5.	Two sets of chromosomes present in the somatic cells of adult individuals.

Ploidy refers to the number of complete sets of chromosomes (genes) present in a cell. The number of chromosomes in a complete set is a fixed characteristic of a species. Humans are diploid with two sets of 23 chromosomes. Fruit flies are diploid with two sets of 4 chromosomes. Sexually reproducing organisms are diploid, each somatic cell of an organism has two complete sets ("di" is a prefix indicating 2.). To complete a life cycle and reproduce new members of a species, mating is required. Mating brings a donation from a male and a donation from a female together. However, if the male and female cells remain diploid, the fertilization will result in a tetraploid zygote. In general, these are not viable. A mechanism is needed to form special haploid cells, gametes. The diploid set is split precisely into two complete haploid sets. That mechanism is meiosis.

The complete set of chromosomes of a species is also the complete set of genes of a species, the genome. (Yes, there is a minor contribution from mitochondria and chloroplasts. Inheritance of this information is "cytoplasmic".)

Please answer the following questions:

1. How many chromosomes in a brain cell of a fruit fly? How many chromosomes are in a liver cell of a human? Explain both answers.

2. How many chromosomes are in a fruit fly unfertilized egg? How many chromosomes are in a human egg? Explain both answers.

3. Why is meiosis necessary for sexually reproducing organisms? How many chromosomes are in a human zygote? Relate the two answers.

4. What is a gene allele? Suppose there is a gene called "bingo" and it is present once in a complete haploid set. How many alleles of "bingo" does a diploid individual have? How many copies or versions of the gene "bingo" are present in a diploid individual?

5. Modern DNA sequencing clearly identifies alleles by showing the different DNA sequence of each allele. These alleles may be termed structural alleles (I coined the term for this problem.). Classical genetics only dealt with phenotypes or visible traits. As a result, alleles of genes were identified by functionality, usually normal or non-functional. Using your knowledge of gene structure and gene expression, postulate a relationship between structural alleles and functional alleles. (include relative amounts; more, less, or equal).

The first sign of cytokinesis in a plant cell is the formation of a __.

In order for a cell to become cancerous, oncogenes must be __ and tumor suppressors __.

An __ is any gene that helps transform a normal cell into a tumor cell.

In humans, cells that produce gametes are collectively called ___.

During what stage of the cell cycle does DNA replicate?

A diploid karyotype is abbreviated by ___.

True or False: Human cells have 23 pairs of chromosomes.

The chromosomal designation for a human male is ___.

True or False: Germ cells undergo meiosis.

What is the process by which homologous chromosomes exchange genetic material?

Who made the most lasting impression on the science of genetics?

Ture or False: During anaphase duplicate chromosomes split apart.

Alternate forms of the same gene are called ___.

What did Mendel choose for his genetic experiments?

True or False: When Mendel crossed short (tt) pea plants with short (tt) pea plants, the offspring were all short.

BIOLOGY 1A03 Lecture Notes - Lecture 5: Centrosome, Cytokinesis, Microtubule

BIOLOGY 1A03 Full Course Notes

Document Summary

Get access

Related Documents

BIOLOGY 1A03 Lecture 2: Theme 5: Module 2 - Meiosis

BIOLOGY 1A03 Lecture Notes - Lecture 17: Homologous Chromosome, Sister Chromatids, Allele

BIOLOGY 1A03 Lecture Notes - Lecture 20: Meiosis, Metaphase, Nondisjunction

Related Questions