Chapter 10 connect

When a chromosome is broken in two places and reconnected so that a region is flipped from the normal order, this is called

A. inversion.

Which of the following is a correct sequence of cells in spermatogenesis?

A. spermatogonium -> primary spermatocyte -> secondary spermatocyte

Daughter cells produced in meiosis have

B. half the number of chromosomes as daughter cells produced in mitosis.

Synapsis is the side-by-side alignment of

B. homologous chromosomes.

Random orientation of homologous chromosomes occurs in ________ of meiosis.

B. metaphase I

During spermatogenesis, which of the following cells is the first to become haploid?

B. secondary spermatocyte

chromosomal alignment during meiosis I

Bivalents independently align at metaphase plate Each chromosome pair contains four chromatids Picture: two chromatids over 2 chromatids ( blue red red blue)

Consider a cell that has four pairs of chromosomes. What is the number of possible chromosome orientations in that cell?

C. 16

Watch the video, then arrange the following events in the proper order in which they occur during meiosis I. 1 = Separation of homologous chromosomes 2 = Crossing-over 3 = Independent assortment

C. 2,3,1

Which of the following is unique to meiosis?

C. crossing-over

Euploidy

Contains the correct number of chromosomes Very High viability

The orientation of each tetrad at the spindle equator is

D. Random

Separation of ________ occurs in anaphase II of meiosis.

D. Separation of ________ occurs in anaphase II of meiosis.

At the end of meiosis II, there are

D. four haploid cells, with each chromosome consisting of a single chromatid.

At the end of meiosis I, each daughter cell is

D. haploid, and each chromosome consists of two chromatids.

A cross-over in meiosis is an exchange of genetic material between

D. nonsister chromatids of homologous chromosomes.

The spindle apparatus is fully formed by the end of

D. prometaphase II.

Which of the following occurs when a piece of one chromosome breaks off and is attached to another nonhomologous chromosome?

D. simple translocation

The number of cells produced in meiosis is

D. twice the number of cells produced in mitosis.

These chromosomes contain genes in the same location that code for the same type of traits, but individual traits could be ______ for each.

Different

Which of the following describes meiosis II in humans

E. 1N --> 1N

Which of the following statements about crossing-over is TRUE?

E. None of these answer choices are true.

T/F: Crossing-over occurs in metaphase I.

False

T/F: Crossing-over has no effect on the genetic makeup of the resulting gametes.

False

T/F: Daughter cells produced in meiosis are identical.

False

T/F: Each orientation of chromosomes produces gametes with the same genetic information from each parent.

False

T/F: Meiosis II of spermatogenesis results in the formation of secondary spermatocytes.

False

T/F: Replication of chromosomes occurs between meiosis I and meiosis II.

False

T/F: The number of possible chromosomal orientations during metaphase I is equal to the number of chromosome pairs raised to the 2nd power.

False

T/F:Independent assortment occurs during prophase I. True

False

_______ with only one X chromosome have the genotype _____ and are said to have_________ syndrome. They tend to have physical differences and _________ reproductive organs, but tend to lead normal lives with __________treatment.

Females, XO, Turner, underdeveloped, hormone

_________with an extra X chromosome have the genotype ____ are are said to have _________ syndrome. They tend to be very tall and lean and can have learning difficulties and reproductive problems, but are often typically developed otherwise.

Females, XXX, Poly X

Turner syndrome

Genetically and physically female example of monosomy causes underdevelopment of reproduction organs and can cause physical differences

Klinefelter syndrome

Genetically and physically male example of trisomy causes underdevelopment of reproductive organs learning difficulties and long limbs

During independent assortment, _______chromosomes separate.

Homologous

Prophase I or Meiosis I

Homologous chromosomes pair up crossing over may occur

_______with an extra Y chromosome have the genotype _____ and are said to have______ syndrome. They tend to be tall, have persistant acne, and have speech and reading problems.

Males, XYY, Jacobs

Duplications

May or may not cause physical abnormalities Occurs when the same piece is repeated within a chromosome

Label the componetnts of the human life cycle in the correct order (starting from the human feet)

Meiosis, n, n, fertilization, zygote 2n,2n,Mitosis, 2n, mitosis

During _________, _________align independently along the equator. (2nd)

Metaphase I, homologues

Monosomy

Missing one chromosome from a pair very limited viability results from nondisjunction A type of aneuploidy or incorrect number of chromosomes

Inversions

Occurs when a piece of a chromosome breaks and reattaches upside down May or may not cause physical abnormalities

Meiosis I

Results in 2 genetically diverse haploid nuclei crossing-over occurs during synapsis Homologous chromosomes pair up during prophase Homologous chromosomes align at the spindle equator during metaphase

Mitosis

Results in 2 genetically identical diploid nuclei A diploid number of chromosomes align at the spindle equator during metaphase.

Meiosis II

Results in 4 gentically diverse haploid nuclei A haploid number of chromosomes align at the spindle equator during metaphase

T/F: A chromosomal mutation is a substantial change in the structure of a chromosome or chromosomes.

True

T/F: During spermatogenesis, spermatids differentiate into spermatozoa.

True

T/F: In animal cells, cell division is accomplished by the formation of a cleavage furrow.

True

T/F: At the end of meiosis I, there are two haploid cells, each with two sister chromatids per chromosome.

True

T/F: Both inversions and translocations can lead to overall deficiencies and duplications of genetic material. True

True

T/F: Chromosome duplication occurs prior to both mitosis and meiosis.

True

T/F: Crossing-over occurs during prophase I of meiosis.

True

T/F: Telophase II of meiosis is basically prophase I in reverse.

True

T/F: The period between meiosis I and II is termed interkinesis.

True

Life cycle of plants

Vegetative state can be 2n or n Alternation of generations is seen where the haploid phase alternates with the diploid phase The haploid phase of the life cycle produces gamete nuclei without the need for meiosis

The sex chromosomes in males are X and ____; the sex chromosomes in females are the X and ____.

Y,X

During________, homologues separate.(3rd)

anaphase I

During________, the sister chromatids separate and move towards the poles.(7th)

anaphase II

Homologues separate and move to opposite ends of the cell where they are split into genetically ______ daughter cells. (5th)

different

If an egg that contains 22 chromosomes instead of 23 chromosomes is fertilized by a normal sperm, _______is said to have occurred.

monosomy

These chromosomes stay close together, and_________ chromatids exchange genetic material, an event also known as _______ (3rd)

nonsister, crossing-over

The___________ breaks down and homologues are temporarily held together by ________, or regions where the nonsister chromatids are attached.( 4th)

nucleoprotein lattice, chiasmata

A ___________ forms to hold the bivalents together so that the DNA of the duplicated chromosomes of each homologue pair is aligned. This forms a________, or four chromatids grouped together. (2nd)

nucleoprotein lattice, tetrad

During meiosis I, if both members of a homologous pair go into the same daughter cell,___________ is said to occur and no normal gametes are produced.

primary nondisjunction

During_______, the nuclear envelope fragments, spindle fibers begin to form, and condensed homologues undergo______ (1st)

prophase I, synapsis

During _______, each duplicated chromosome attaches to the spindle. (5th)

prophase II

This separation is_______; it is due to their alignment down the metaphase plate.

random

During meiosis II, if the sister chromatids fail to separate and both daughter chromosomes go into the same gamete, ________ is said to occur. Half the gametes are aneuploid while the other half are euploid.

secondary nondisjunction

After_________, the resulting 2 daughter nuclei are_____meaning they each contain one chromosome from each homologue. (4th)

telophase I, haploid

During _______, the spindle disappears and upon completion of cytokinesis, 4 _____ daughter cells result. (8th)

telophase II, haploid

Life cycle of animals

vegetative stat is 2n Gametes are the only haploid phase of life cycle Meiosis results in gametophytes

Humans have ___ pairs of chromosomes; members of each pair are called __________ chromosomes, as seen in A above.

23, homologous

Meiosis I or II image selection (bottom row left to right)

2n=4, 2n=4, m=2, n=2

The exchange of genetic material between nonsister chromatids is called crossing-over and occurs during which phase of meiosis?

A. Prophase I

What is the overall purpose of meiosis?

A. To produce four genetically different haploid cells

2n

Also called diploid seen in somatic cells

1n

Also called haploid Seen in animal gametes

Centromeres divide during

B. Mitosis and Meiosis II

Which cells in the body originated through the process of meiosis?

B. Sperm and egg cells

Which of the following causes an extra copy of a chromosomal region to occur?

B. duplication

Spermatogenesis occurs in the

B. seminiferous tubules.

Select all of the following ways in which meiosis II is different than meiosis I.

D. All of the answer choices are correct.

Which of the following events occur during prophase I?

E. breakdown of the nuclear envelope, condensation of chromosomes, and movement of centrosomes

A tetrad is made up of

E. two homologous chromosomes, each consisting of two chromatids.

Oogenesis: Meiosis II

Egg

Translocation

Examples include Alagille syndrome, chronic myelogenous leukemia, and Burkitt leukemia Occurs when pieces of a chromosome are exchanged between nonhomologous pairs

________ with an extra X chromosome have the genotype ________ and are said to have _______r syndrome. They tend to have long limbs, __________reproductive organs, and can have learning difficulties

Males, XXY, Klinefelter, underdeveloped

Meiosis I or II image selection (top row left to right)

Meiosis I, Meiosis II

asexual reproduction

Relies of mutations to generate variation. offspring are genetically identical to parents. Necessary when cells need to be genetically identical, such as with skin cells or blood cells

sexual reproduction

Reproduction itself generates genetic variation. Offspring are genetic combinations of both parents and are thus genetically different from individual parents. Variation occurs because of crossing over during synopsis and independent assortment. Necessary when genetic variation is beneficial, such as a sudden shift in the environmental conditions.

Trisomy

Results from nondisjunction A type of aneuploidy or incorrect number of chromosomes limited viability has an extra chromosome within a pair

Oopenersis: Meiosis I

Secondary Oocyte

Spermatogensis: Meiosis I

Secondary spematocytes

When chromosomes replicate, as shown in B, each of the replicates are called ___________ __________.

Sister chromatids

These ______ are exact copies of each other and contain the same genes in the same locations with the ____ traits.

Sister chromatids, same

Spermatogenesis: Maturation

Sperm

Spermatogensis: Meiosis II

Spermatids

This results from ________ copy of chromosome 21, usually donated from the ________

an extra, egg

There are 22 pairs of chromosomes called _______ and one pair of chromosomes called ____________.

autosomes, sex chromosomes

During meiosis I, _____________ separate and move towards opposite ends of the poles.

homologous chromosomes

During ______, homologous chromosomes line up side by side, an event also known as _____. (1st)

meiosis 1, synapsis

Individuals with Down syndrome tend to have similar characteristics, including short stature, an extra eyelid fold, stubby fingers, a fissured tongue, and sometimes ____________

mental disabilities.

The maternal or paternal homologue may be oriented toward either ______

pole

This variation helps in the long-term _______ of the species

survival

If an egg that contains 24 chromosomes instead of 23 chromosomes is fertilized by a normal sperm, _________ is said to have occurred.

trisomy

An example of nondisjunction in autosomes is_______ also called Down syndrome.

trisomy 21,

This randomized separation aids in genetic ________ of offspring.

variation

Mitosis

Primary spermatocytes Primary oocytes

Which of the following events occur during anaphase I?

A. separation of homologous chromosomes

How many tetrads (bivalents) are formed in a cell with 20 chromosomes at the beginning of meiosis I?

C. 10

During anaphase I of meiosis, ________ move towards opposite cell poles, whereas during anaphase II of meiosis, ________ are separated.

C. homologous chromosomes; sister chromatids

Deletions

Examples include Willams syndrome and cri du chat syndrome Occurs when pieces of a chromosome are lost

chromosomal alignment during Mitosis

Individual chromosomes align at the metaphase plate Each chromosome contains two chromatids Picture: all chromosomes lined up in a straight line down the center

Prophase of Mitosis

No pairing of chromosomes crossing-over does not occur

The chance of having a child with Down syndrome__________with maternal age due to the greater chance of ___________ occurring among developing egg cells.

increases,nondisjunction

During _______, duplicated chromosomes line up at the equator.(6th)

metaphase II

During meiosis II, __________ separate and move towards opposite ends of the poles.

sister chromatids

T/F:Germ-line cells are haploid but gametes are diploid. True

False