Biology Chapter 9 part I and II

Select all of the following that are true about meiosis.

-creates four haploid cells from one diploid cell -produces gametes with half the number of chromosomes as compared to somatic cells -includes two cell divisions

Place the events of egg production in correct order.

1. Diploid oogonium divides by mitosis to produce a primary oocyte 2. Primary oocyte begins meiosis 3. Meiosis I produces one haploid secondary oocyte and one haploid polar body 4. Meiosis II of the secondary oocyte produces one haploid ovum and one haploid polar body

Place the events of sperm production in the correct order, beginning with the first step at the top.

1. Diploid spermatogonia germ cells mitotically divide 2. Primary spermatocyte begins meiosis 3. Meiosis I produces two haploid secondary spermatocytes 4. Meiosis II produces four haploid spermatids 5. Maturation produces four, motile sperm

Rank the steps of meiosis I in the order in which they occur, beginning with the first phase at the top.

1. prophase I 2. metaphase I 3. anaphase I 4. telephase

Rank the steps of meiosis II in the correct order in which they occur, beginning with the first step at the top.

1. prophase II 2. metaphase II 3. anaphase II 4. telephase II

How many rounds of cell division occur in meiosis?

2

If an animal has 6 chromosome pairs in its cells, then 64 combinations of chromatids are possible for a gamete. If both male and female gametes have 64 possible chromosome combinations, how many genetically unique zygotes could be produced due to random fertilization? (Assume crossing over does not occur.)

About 4,000

An extra copy of chromosome 21 causes

Down syndrome

______ results in genetically identical daughter cells, whereas ______ results in genetically different daughter cells.

Mitosis; meiosis

What results in a random mixture of paternal and maternal genetic material in each daughter cell during meiosis?

Random orientation of chromosome pairs during metaphase I

Select the true statement about human gametes.

Sperm and egg cells are very different in size.

Nondisjunction of the ______ chromosome during meiosis can produce offspring that are XXX or XXY.

X

Select all the possible results of nondisjunction in sex chromosomes.

XXX zygote gamete contains an extra X gamete contains an extra Y gamete is missing a sex chromosome

What cycle is shown in the picture?

alternation of generations

A cell that has one or a few extra or missing chromosomes is called a(n) _____ cell.

aneuploid

A cell that results from nondisjunction is called a(n) ______ cell.

aneuploid

In ______ reproduction, genetically identical offspring are produced, while in ______ reproduction, offspring are genetically different from each other.

asexual; sexual

Select all the organisms that can produce gametes for sexual reproduction.

bread molds ferns humans

In eukaryotes, a molecule of genetic material and its associated proteins form a(n) ___________________, of which humans have 46 in each cell.

chromosome

A single molecule of DNA and its associated proteins form a

chromosome.

This image shows two ways that ______ during meiosis I to generate different combinations of chromatids in resulting gametes.

chromosomes can arrange

Short segments of DNA are exchanged between homologous chromosomes during prophase I in a process called _________________ over.

crossing

Select all of the mechanisms that generate genetic variability in sexual organisms.

crossing over random fertilization random orientation of chromosomes

Chromosomal ___________________ is an abnormality that results in the loss of one or more genes from a chromosome.

deletion

If the left chromosome is normal, what form of chromosome abnormality is shown in the right chromosome in the picture?

deletion

Located in the ovaries and testes of animals, specialized cells called germ cells are ______ and undergo meiosis to produce ______.

diploid; gametes

Select all of the following that are true about spermatids.

equal-sized haploid specialize into mature sperm

Crossing over, random orientation of chromosomes, and random fertilization are mechanisms involved in meiosis and sexual reproduction that generate ____________________ diversity.

genetic

The chromosomes of offspring are not identical to those of their parents or siblings because ______ is shuffled during meiosis.

genetic information

Sexual reproduction produces ______, while asexual reproduction produces ______.

genetically different offspring from two parents; genetically identical offspring from one parent

In animals, specialized diploid cells that undergo meiosis are called

germ cells.

A(n) ______ cell contains only one copy of each chromosome.

haploid

Select all of the following that are true about secondary spermatocytes.

haploid will enter meiosis II

Crossing over is the process in which

homologous chromosomes physically exchange pieces.

A cell in which homologous chromosomes are arranged in pairs along the equator of the cell is in what phase?

meiosis I

In meiosis shown in the image, homologous chromosomes separate in step A, which is called ______, and four haploid nuclei are formed in step B, which is called ______.

meiosis I; meiosis II

Dividing cells that contain only one chromosome from each homologous pair lined up singly at the equator of the cell must be undergoing

meiosis II.

In the alternation of generations plant life cycle,

multicellular haploid and diploid structures are present.

A process called _______________ is an error in meiosis in which chromosomes fail to separate and a gamete with too many or too few copies of a particular chromosome can be produced.

nondisjunction

What produces gametes with a missing or extra chromosome and results in embryonic, fetal, or infant death or a trisomic individual?

nondisjunction

Cells that are haploid contain

one full set of genetic information.

The production of egg cells is called

oogenesis.

The mature, haploid egg cell of a human female is also called a(n)

ovum.

What occurs during meiosis but not mitosis?

pairing of homologous chromosomes

A(n) ______ cell has at least one extra set of chromosomes.

polyploid

What is a cell with a complete extra set of chromosomes called?

polyploid

In human females, specialized cells that are diploid and will enter meiosis I are called

primary oocytes.

In human males, specialized cells that are diploid and will enter meiosis I are called

primary spermatocytes.

Select all of the following that are true of an ovum (mature egg cell).

produced by meiosis II haploid

Select all of the following that are true about primary oocytes.

produced by mitosis diploid will enter meiosis I

Select all of the following that are true about nondisjunction.

produces abnormal gametes caused by malformed spindle fibers can occur at either anaphase I or anaphase II

Crossing over only occurs in

prophase I of meiosis.

In sexual reproduction, exactly what egg cell matures and what sperm cell fertilizes the egg is

random and results in genetic variability.

Select all of the following that describe mitosis.

results in 2 daughter cells starts with a diploid cell and results in diploid cells

Meiosis I in human males produces two ______, which are haploid and will enter meiosis II.

secondary spermatocytes

Two ______ undergo meiosis II to produce four spermatids.

secondary spermatocytes

Humans reproduce via

sexual reproduction.

Select the two main functions of meisois.

shuffle genetic information reduce chromosome number to half in daughter cells

Human gametes are haploid cells and include two types: ______________ , which are lightweight and can swim; and _____________ , which are large and packed with organelles.

sperm; egg

Meiosis II in human males results in four haploid ______, which mature into four haploid ______.

spermatids; sperm

The production of sperm cells is called

spermatogenesis.

Select all of the following that can result from nondisjunction in humans.

trisomy failed development due to missing genetic material an extra copy of a chromosome

The most common cause of Down syndrome is

trisomy 21.

Select all of the following that are true about primary spermatocytes.

will enter meiosis I diploid produced by mitosis of spermatogonium