BIOL 115 Lecture Notes - Lecture 21: Chromosome, Mendelian Inheritance, Sex Linkage

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rosebutterfly172

31 Aug 2020

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Explain the relationship between structure and behaviour of chromosomes during meiosis and inheritance of genes. Chromosome behaviour during meiosis leads to genetic variation, at two stages: during crossing over, when chromosomes randomly segregate and paternal and maternal chromosomes assort independently of each other. Explain the role of gamete formation and sexual reproduction in variability of offspring. Gametes form by meiosis, where recombination of genetic material takes place as a result of: the individual alleles of maternally and paternally derived chromosomes to assort independently. One cell undergoes two meiotic divisions to generate four haploid cells. The gene in each haploid cell are a new combination of parental genes. The new combination results from both crossing over and random segregation, allowing. Crossing over: crossing over of genetic material during meiosis results in the exchange. Random segregation: during meiosis, genes on different chromosomes sort. Random fertilisation: when a male and female, from two different gametes randomly of genes between chromosomes pairs.

Related Questions

Which statements pertaining to genetic variability are correct? Check all that apply (note that wrong answers will be deducted from right answers)!

Crossing over is defined by the exchange of chromosome pieces during metaphase one of meiosis.

If a germ cell (i.e. parent cell before meiosis) had only two pairs of homologous chromosomes (i.e. 4 chromosomes total) there are 2 possible combinations of maternal and paternal chromosomes in gametes.

Siblings produced by sexual reproduction are different because sperms are different from one another and eggs are different from one another, and the combination of an egg and sperm is basically unique.

Random fertilization means that all possible combinations of eggs and sperm are equally likely, i.e. it is pure chance which sperm fuses with which egg.

Individual chromosomes contain thousands of genes. This means that during each crossing over event, more than one gene is exchanged between paternal and maternal chromosomes.

limedonkey586

What is the purpose of meiosis?

To enable an organism to produce gametes

To allow for growth

To allow an organism to replace damaged cells

Question 2

Select one answer.

10 points

Mitosis results in ________ and meiosis results in ________.

gametes, somatic cells

gametes, gametes

somatic cells, somatic cells

somatic cells, gametes

Question 3

Select one answer.

10 points

Which of the following tasks is accomplished through the processof meiosis?

Cell growth

Production of sperm or eggs

Replacement of dysfunctional cells

Question 4

Select one answer.

10 points

What advantage does sexual reproduction have over asexualreproduction?

All other selections are true.

Sexual reproduction provides more genetic variability

Sexual reproduction doubles the number of chromosomes in aspecies

Sexual reproduction is more efficient

Question 5

Select one answer.

10 points

Crossing over occurs between homologous chromosomes during whatstage of cell division? (Read each option carefully.)

Prophase I of meiosis

Prophase of mitosis

Prophase II of meiosis

Interphase

Question 6

Select one answer.

10 points

Corn has 20 chromosomes. When corn undergoes meiosis how manychromosomes are found in the gametes?

Question 7

Select one answer.

10 points

Homologous chromosomes separate and are pulled to opposite sidesof the cell during what stage of cell division? (Read each optioncarefully.)

Metaphase I of meiosis

Anaphase II of meiosis

Anaphase I of meiosis

Anaphase of mitosis

Question 8

Select one answer.

10 points

Mitosis results in ______ cells and meiosis results in _______cells.

diploid, haploid

haploid, diploid

diploid, diploid

haploid, haploid

jadepug655

In order to move from G1 to S-phaseâ¦

Select one:

a. Cyclin-Cdk must phosphorylate cytochrome c, thereby inactivating it.

b. Cyclin-Cdk must phosphorylate cytochrome c, thereby activating it.

c. Cyclin-Cdk must phosphorylate RB, thereby inactivating it.

d. Cyclin-Cdk must phosphorylate ADP to make enough ATP for all that DNA synthesis.

e. Cyclin-Cdk must phosphorylate RB, thereby activating it.

How is meiosis different than mitosis?

Select one:

a. Meiosis is found only in juvenile organisms while mitosis is found at all life stages.

b. Cytokinesis is skipped during meiosis but not during mitosis.

c. During anaphase II of meiosis chromosomes segregate randomly while in mitosis they do not.

d. Meiosis is uncontrolled while mitosis is rigorously controlled.

e. During metaphase I of meiosis homologous chromosomes pair up together and in mitosis they do not.

C.)

âCrossing overâ during meiosis leads toâ¦

Select one:

a. the exchange of DNA on a maternal chromosome for DNA on paternal chromosome.

b. free radical formation and DNA damage.

c. incomplete formation of chiasmata.

d. many mitotic errors and mutations.

e. transcription and translation.

âNon-disjunctionâ during meiosis leads toâ¦

Select one:

a. robust, mutation-proof gametes.

b. parthenogenic reproduction.

c. larger zygotes.

d. the wrong number of chromosomes in the daughter cells.

e. is important for generating heritable genetic variability.

amaranthdolphin658

BIOL 115 Lecture Notes - Lecture 21: Chromosome, Mendelian Inheritance, Sex Linkage

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