Chapter 3: Chromosomes and Inheritance

chromosomes are best defined as

the structures within living cells that contain the genetic material

the units of inheritance that code for proteins

genes

mitosis results in

two daughter cells containing the same number and type of chromosomes as the original parent cell

a typical human cell has ____ pairs of chromosomes for a total of ___

23; 46

meiosis produces cells that contain

half the number of chromosomes found in other cells within the same organism

the ___________ of eukaryotic cells is the organelle that primarily contains the genetic information

nucleus

most human somatic cells have a total of _____ chromosomes

46 (23 pairs, each containing 2 chromosomes)

a diploid cell is defined as a cell that has

two sets of chromosomes

a nucleus is

an organelle found in eukaryotic cells that contains the hereditary material

what does a haploid cell contain?

a single set of chromosomes

the structures within all living cells that contain the genetic material are called

chromosomes

a haploid cell is represented by n and a diploid cell by 2n. the n refers to______

a set of chromosomes

the kind of nuclear division followed by cell division that results in two daughter cells containing the same number and type of chromosomes as the original parent cell is called______

mitosis

after replication, each chromosome consists of two copies called ____, that are attached by a centromere

sister chromatids

in eukaryotes, ______ is the type of cell division that is responsible for the production of gametes

meiosis

in this picture the circled chromosomes are

homologous chromosomes

in a _____ cell, each type of chromosome is a member of a pair

diploid

a(n) _____ cell has a single set of chromosomes

haploid

in a diploid cell, each member of a pair of chromosomes is called a(n)

homolog

in humans, a diploid cell contains two sets of chromosomes, for a total of ________ chromosomes. In contrast, a gamete (sperm or egg cell) contains only a single set, consisting of ____ chromosomes

46; 23

what is the name for the diffuse complex of DNA and proteins in a eukaryotic cell?

chromatin

the two copies of a replicated chromosome are called ____

sister chromatids

during the G1 phase of interphase, ____

cells grow in size

in this picture the circled chromosome is composed of two

sister chromatids

during prophase of mitosis, chromosomes _______ into discrete structures. Furthermore, the two _______ separate moving towards the moles and the mitotic _______ begins to form

condense, centrosomes, spindle

select the events that occur during prometaphase

chromosomes attach to the microtubules through the kinetochore

the nuclear envelope completely breaks down

chromosomes inherited from each parent that match in size, shape, and banding are called

homologs or homologous

the mitotic spindle of an animal cell has two poles, which originate from the two ______

centrosomes

what. is chromatin?

a complex between DNA and proteins that is found in eukaryotic cells

during which part of interphase do cells achieve the majority of their growth?

G1

during ____ of mitosis, chromosomes are aligned along the equatorial plate, or the center of the cell

metaphase

select the events that occur during prophase of mitosis

the nucleolus becomes less visible

the centrosomes move apart

the chromatin condenses into more compact structures

During ______, pairs of sister chromatids become attached to kinetochore microtubules which emanate from opposite poles of the cell.

prometaphase

the mitotic ______ contains three types of microtubules: axial, polar, and kinetochore microtubules

spindle

what event occurs during metaphase of mitosis?

pairs of sister chromatids become organized in a single row

which of the following events occurs during anaphase of mitosis?

sister chromatids separate from each other and head to opposite poles

if the original diploid mother cell had eight chromosomes, a cell in telophase of mitosis would have _____ nuclei, each with ____ chromosomes

two; eight

which of the following best describes the outcome of mitosis and cytokinesis in human somatic cells?

2n --> 2n

what ensures that cell cycle events occur in the proper sequence?

checkpoints

cells that are destined to undergo meiosis and produce gametes are called ______ cells

germ or germ-line

during anaphase, each chromatid moves towards the pole to which it is attached. this movement is caused by the shortening of the

kinetochore microtubules

all of the following events occur during telophase except that the

pairs of sister chromatids begin to separate from each other (this occurs in anaphase)

mitosis and cytokinesis result in the formation of ____

two genetically identical daughter cells

synapsis is the process by which _____

homologous chromosomes recognize each other and begin to align themselves in prophase I

when a cell evaluated the results of previous steps, this is called a(n)

checkpoint

during the zygotene stage of meiosis I, the _____ complex aligns homologous chromosomes

synaptonemal

a _____ cell is any cell of the body that is not a gamete or precursor to a gamete

somatic

a bivalent, or tetrad, consists of ____

two pairs of sister chromatids of homologs

during which of the following phases are tetrads organized along a plate in the center of the cell?

metaphase of meiosis I

during prophase of meiosis I, homologous chromosomes recognize and begin to align with each other via a process called _____

synapsis

consider an organism that has four pairs of chromosomes (2n = 8). at the end of meiosis I, each cell would have _____ chromosomes and _____ chromatids

four; eight

the zipper like structure in the center of this picture represents ____

the synaptonemal complex

During what stage of meiosis II does the nuclear envelope break down?

prophase II

A bivalent is also called a ______ because it is composed of four chromatids.

tetrad

select the aspects of meiosis that contribute to genetic diversity in a population

independent assortment

crossing-over

in _____of meiosis, the bivalents (which are also termed tetrads) are aligned along the center of the cell

metaphase I

select the events that occur during mitosis

sister chromatids separate and move to opposite poles

chromosomes condense, and nuclear envelope breaks down

kinetochores begin attaching to spindle fibers

in 1903, Walter Sutton suggested that chromosomes carry Mendel's hereditary units. Select the reasons he gave for this proposal.

in all cells derived from a fertilized egg, half of the chromosomes and genes have maternal origin, and half have paternal origin

both chromosomes and alleles of unrelated genes assort independently

during meiosis, homologous chromosomes and alternative alleles of a gene pair then separate to different gametes

every cell has two copies of each chromosome, and there are two copies of each kind of gene

which of the following best describes the outcomes of meiosis I in humans?

2n --> 1n

Mendel's law of ______ can be explained by the homologous pairing and separation of chromosomes during meiosis

segregation

if the chromosomes decondense during the preceding interphase, they recondense during ______ II of meiosis

prophase

meiosis increases genetic diversity in a population through crossing-over and by _________ assortment of parental chromosomes

independent

the random arrangement of homologs along the metaphase plate in meiosis I is consistent with Mendel's law of _____ ____

independent assortment

which of the following statements about mitosis and meiosis of humans is true?

mitosis produced two diploid daughter cells, while meiosis produces four haploid daughter cells

in 1902-1903, Walter Sutton proposed that _____ contain genes

chromosomes

the behavior of chromosomes during meiosis explains Mendel's law of segregation. Specifically, a gamete contains only one copy of each type of chromosome because of which of the following?

the homologs segregate during meiosis I and the sister chromatids during meiosis II

which aspect of chromosome behavior is consistent with Mendel's law of independent assortment?

independent alignment of different homologous pairs along the metaphase I plate