Biology: Concepts and Connections, 7th Edition, Chapter 8

Chiasma

(greek for cross) The sites of crossing over appear as X-shaped regions. A place where two homologous (non sister) chromatids are attached to each other.

Locus

(plural- loci) A particular place on the chromosome

In metaphase of mitosis, each chromosome contains how many chromatids?

2 sister chromatids

The haploid number for humans is

23, n=23

A human cell at metaphase contains how many sets of duplicated chromosomes?

23, they occur in matched pairs

The total number of combinations of chromosomes that meiosis can package into gametes for any species is

2^n, n=haploid number

For humans the diploid number is

46, 2n=46

Researchers have discovered how many different types of growth factors that can trigger cell division?

50

In humans, 46 chromosomes is equal to how many chromatids?

92 chromatids

The cell plate grows

Outward

Which of the following statements regarding prokaryotes is false?

Prokaryotic chromosomes are more complex than those of eukaryotes

Crossing over begins very early in what phase of meiosis?

Prophase I

Duplicated homologous chromosomes pair to form tetrads in what phase?

Prophase I

The five stages of mitosis

Prophase, prometaphase, metaphase, anaphase, telophase

Cell division

Reproduction at the cellular level, requires the duplication of chromosomes, and sorts new sets of chromosomes into the resulting pair of daughter cells.

What function does cell division play in an amoeba? In your body?

Reproduction; Growth, development, and repair.

Sexual Reproduction

Requires fertilization of an egg by a sperm. Testes and ovaries. Takes half of the genes from both parents.Not Identical.

Chromosomes duplicate in which sub phase?

S phase

Tetrads

Sets of four chromatids, with each pair of sister chromatids joined at the centromeres

Vascular endothelial growth factor (VEGF)

Stimulates the growth of new blood vessels during fetal development and after injury

Homologous chromosomes come together as pairs in a process

Synapsis, In prophase I

The S in S phase stands for what?

Synthesis of DNA, or DNA replication

At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids.

Telophase I

Autosomes

The 22 remaining pairs of chromosomes found in males and females.

Translocation

The attachment of a chromosomal fragment to a non homologous chromosome. May be reciprocal: two non homologous chromosomes may exchange segments

Trisomy 21

The basis of Down syndrome

What cycle multiplies cells?

The cell cycle

Telophase

The cell elongation that started in the anaphase continues. Daughter nuclei appear at the two poles of the cell as nuclear envelopes from around the chromosomes. The reverse of prophase

What happens in all three sub phases of the interphase stage?

The cell grows.

The total number of chromosomes is called

The diploid number (2n)

Metaphase

The mitotic spindle is fully formed, poles at opposite ends. Chromosomes convene on the metaphase plate, an imaginary plane equidistant between the two poles of the spindle.

Prometaphase

The nuclear envelope breaks into fragments and disappears. Microtubules are now highly condensed. Centromere region, each sister chromatid have protein structure called a kinetochores.

Meiosis

The production of egg and sperm cells involves a special type of cell division. Produces haploid gametes in diploid organisms

Genetic Recombinant

The production of gene combinations different from those carried by the original parental chromosomes.

Life cycle

The sequence of stages leading from the adults of one generation to the adults of the next.

Cleavage furrow

a shallow indentation in the cell surface

With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because they have

a similar but not identical combination of genes.

Tumor

an abnormally growing mass of body cells

Karyotypes

are often produced from dividing cells arrested at metaphase of mitosis

Sarcomas

arise in tissues that support the body (bone, muscle)

Strictly speaking, the phrase "like begets like" refers to

asexual reproduction only

When the cell cycle operates normally, mitosis produces genetically identical cells for

growth, replacement of damaged and lost cells, and asexual reproduction.

Because in meiosis, one duplication of chromosomes is followed by two divisions, each of the four daughter cells produced

has a haploid set of chromosomes and are not genetically identical

Chronic myelogenous leukemia (CML)

is one of the most common leukemias,affects cells that give rise to white blood cells (leukocytes), and results from part of chromosome 22 switching places with a small fragment from a tip of chromosome 9.

Nondisjunction can happen if

meiosis I, if both members of a homologous pair go to one pole or meiosis II if both sister chromatids go to one pole.

In meiosis, how many crossover events occur per chromosome pair?

one to three

During _____ a spindle forms in a haploid cell.

prophase I

Cytokinesis

Begins before mitosis ends, the cytoplasm is divided into two. Occurs along with Telophase.

Anaphase

Begins when the two centromeres of each chromosome come apart, separating the sister chomatids. Chromatids consider full fledged daughter chromosome.

Prokaryotes reproduce by a cell division called

Binary Fission

Alterations of chromosome structure can cause

Birth defects and cancer

Malignant Tumor

Can spread into neighboring tissues and other parts of the body, displacing normal tissue and interrupting organ function as it goes

An individual with a malignant tumor is said to have

Cancer

Leukemias and Lymphomas

Cancers of blood-forming tissues (bone marrow, spleen, lymph nodes

Carcinomas

Cancers that originate in the external or internal coverings of the body (skin, lining of the intestine)

Based on site of origin, cancers are grouped into four categories.

Carcinomas, Sarcomas, Leukemias, and Lymphomas

The process of cell division is a key component of the

Cell cycle

The spindle microtubules emerge from two

Centrosomes

The site of attachment and crossing over.

Chiasma, Nonsister chromosomes join here

Homologous Chromosomes

Chromosomes that have twins resembling its length and centromere position. Two chromosomes of matching pairs both carrying genes controlling the same inherited characteristics.

In animal cells, cytokinesis occurs by a process known as

Cleavage

The first sign of cleavage is the appearance of

Cleavage furrow

Centrosomes

Clouds of cytoplasmic material that in animal cells contain pairs of centrioles. (Microtubule-organizing centers)

As a cell prepares to divide its chromatin

Coils up

Asexual reproduction

Creation of genetically identical offspring by a single parent. (ex. Sea star species). Lone parent and each offspring have have identical genes.

Nonsister chromatids exchange genetic material in a process

Crossing over

Which of the following statements regarding the differences between mitosis and meiosis is false?

Crossing over is a phenomenon that creates genetic diversity during mitosis.

The sources of genetic variability therefore include

Crossing over, Independent orientation of chromosomes, and Random fertilization

Chromatin

DNA in its loose state. DNA in one cell would exceed my own height.

Cells in the human liver do not divide unless the liver is

Damaged

If a fragment of a chromosome is lost or removed, the remaining chromosome will then have a ______.

Deletion

Turner syndrome

Denoted as XO, Lacking one X chromosome, Are females and sterile because their sex organs are underdeveloped. Individuals usually have a short statue and a web of skin between the neck and shoulders

Klinefelter syndrome

Denoted as XXY, Have a extra X chromosome, Individuals are males, but testes are abnormally small and individuals are sterile. Often includes breast enlargement, and other female body characteristics

Sex Chromosomes

Determines an individual's sex

If a fragment from one chromosome joins to a sister chromatid or homologous chromosome, it will produce a ______

Duplication

Cell plate

During telophase, in plant cells, membranous vehicles containing cell wall material collect at the middle of the parent cell. The vesicles fuse forming a membranous disk.

Sister Chromatids

Each chromosome that consist of two copies of DNA molecules, Creating daughter cells.

What gender has fully homologous chromosomes?

Females (XX)

In a living animal, most cells are anchored in a _____ position.

Fixed

Interphase can be divided into three sub phases.

G1 phase (First gap), S phase, G2 phase (second gap)

What are the three major checkpoints in a cell cycle?

G1, G2, M

At which one of the three checkpoints do the chromosomes exist as duplicated sister chromatids?

G2 and M checkpoints

Each _____ has a single set of chromosomes, 22 autosomes plus a sex chromosome. (X or Y)

Gamete

_____ are made by a special sort of cell division called _____, which occurs only in reproductive organs.

Gametes, Meiosis

Which of the following statements regarding genetic diversity is false?

Genetic diversity is enhanced by mitosis.

Each daughter cell produced by meiosis II has only one ______ set of chromosomes.

Haploid

What type of chromosome pairs have different versions of the same gene?

Homologous

Diploid

Humans, animals, many plants are considered this because all body cells contain pairs of homologous chromosomes.

How are chromosomes matched?

In homologous pairs

Somatic cell

In humans, a typical body cell that has 46 chromosomes

Genetic variation in gametes results from

Independent orientation at metaphase I and random fertilization.

Three sources of genetic variability in sexually reproducing organisms

Independent orientation of chromosomes at metaphase I, random fertilization, and crossing over during prophase I or meiosis.

The time when a cell's metabolic activity is very high and the cell performs its various functions with the organism.

Interphase, or growing stage

Most of the cell cycle is spent in what stage?

Interphase, or growing stage about 90% of the time

If a fragment reattaches to the original chromosome but in the reverse orientation.

Inversion

f a chromosome fragment breaks off and then reattaches to the original chromosome, but in the reverse direction, the resulting chromosomal abnormality is called a(n)

Inversion

What type of blood cell is used to prepare a karyotype?

Lymphocytes

Mitotic phase

M phase, The part of the cell cycle when the cell actually divides. Accounts for 10% of the total time required for the cell cycle.

Chromosomes X and Y behave as a homologous pair in

Meiosis

_____ prevents each generation from having twice as much genetic material as the generation before

Meiosis

_____ reduces the chromosome number from diploid to haploid.

Meiosis

All events unique to meiosis happens in

Meiosis I

A human in what phase contains 23 sets of duplicated chromosomes.

Metaphase

All the chromosome pairs orient independently at what phase?

Metaphase I

Tetrads align at the cell equator in which phase?

Metaphase I

Tetrads are aligned at the metaphase plate in what phase?

Metaphase I

During _____ chromosomes align single file along the equator of a haploid cell.

Metaphase II

Meiosis II is virtually identical to _____ because the separate sister chromatids

Mitosis

_____ produce daughter cells with the same number of chromosomes as the parent cells, _____ reduces the chromosome number by half.

Mitosis, meiosis.

What phase is divided into two overlapping stages? What are the stages?

Mitotic phase. Mitosis and Cytokinesis

XXX

Most are normal females with an extra X chromosome

XYY

Most are normal males with an extra Y chromosome (although they tend to be taller than average)

Whats ultimately responsible for genetic diversity in living organisms?

Mutations

Haploid

A cell with a single chromosome set; has only one member of each homologous pair.

The Cell Cycle Control System

A cyclically operating set of molecules in the cell that both triggers and coordinates key events in the cell cycle.

Mitotic Spindle

A football-shaped structure of microtubules that guides the separation of the two sets of daughter chromosomes

The cell cycle consist of two main stages.

A growing stage (interphase) and the actual cell division (mitotic phase)

Benign Tumor

A lump of abnormal cells that remain at the original site. Can be removed by surgery.

Density-dependent inhibition

A phenomenon in which crowded cells stop dividing.

Karyotype

A photographic inventory of an individual's chromosomes arranged in pairs. Shows them condensed and doubled as appeared in metaphase of mitosis

Mitosis

A process, The type of cell division responsible for asexual reproduction and for the growth and maintenance of multicellular organisms.

Growth factor

A protein secreted by certain body cell that stimulates other cells to divide

Hydra

A tiny multicellular animal that reproduces by either sexual or asexual means

How are cancers named?

According to the organ or tissue in which they originate.

These proteins responsible of muscle contraction are

Actin and Myosin

Crossing over

An exchange of corresponding segments between nonsister chromatids of homologous chromosomes

Nondisjunction

An occasional mishap in which the members of a chromosome pair fail to separate.

Cell cycle

An ordered sequence of events that extends from the time a cell is first formed from a dividing parent cell until its own division into two cells

Homologous chromosomes migrate to opposite poles during _____.

Anaphase I

Pairs of homologous chromosomes separate, sister chromatids of each chromosome stay together in what phase?

Anaphase I

Most animal cells exhibit _____ _____; they must be in contact with a solid surface. Ex inside of a culture dish or the extracellular matrix of a tissue to divide.

Anchorage Dependence

What factors affect cell division?

Anchorage, cell density, and chemical growth

Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other?

The sequences are identical.

Gametes

The sperm and egg cells

Metastasis

The spread of cancer cells beyond their original site

Chromosomes

The structures that contain most of the cells DNA

Platelet-derived growth factor

This protein promotes the rapid growth of connective tissue cells that help seal the wound

, there is no chromosome duplication between the end of meiosis I and the beginning of meiosis II. T/F?

True

At the end of meiosis I, There are _____ cells, with each chromosome still having two _____ _____.

Two, sister chromatids

When does the abnormal behavior of a cancer cell begin?

When a normal cell is converted into a cancer cell

When does a chromosome consist of two identical chromatids?

When the cell is preparing to divide and has duplicated its chromosomes but before the duplicates actually separate.

Prophase

Within the nucleus, chromatin fibers become tightly coiled and folded. Cytoplasm, the mitotic spindle begins to form as microtubules rapidly grow out from the centrosomes, they begin to move away from each other

When animal cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the bottom of the dish. This arrest of division is an example of

density-dependent inhibition.

In mitosis, the nucleus and its contents divide and are evenly distributed forming

two daughter nuclei

Interphase stage

when the cell roughly doubles everything in its cytoplasm and precisely replicates its chromosomal DNA