BIO 105 — Test 3

a normal female.

A human karyotype showing 22 pairs of autosomes and two X chromosomes would be

kinetochore

A protein structure in the centromere of each sister chromatid that attracts and binds spindle microtubules during prometaphase

Cytokinesis which is when the cytoplasm is divided and two daughter cells are formed.

After mitosis, what process occurs?

Fertilized egg

All multicellular organisms, begin with a _.

Anuploid - organisms with abnormality chromosome number Euploid - organisms with normal chromosome number

Aneuploid vs. Euploid

Centromere

Area where the chromatids of a chromosome are attached

1. These methods of reproduction do not require another organism of the opposite sex. 2. There is no need to expend energy finding or attracting a mate. 3. That energy can be spent on producing more offspring.

Benefits to asexual reproduction

Alternation of generations

Category of life in which haploid and diploid are apparent at one point

Diploid-dominant

Category of life in which the diploid stage is the most obvious stage and there is no multicellular haploid stage (nearly all animals)

Haploid-dominant

Category of life in which the haploid stage is multicellular and the most obvious life stage, and there is no multicellular diploid stage (fungi)

Tumor suppressor gene

Certain genes can code for negative-regulator proteins such as p53, a common _, that effectively halts the cell cycle process until certain actions are completed.

Duplication, deletion, inversion, or translocation

Chromosome structural abnormalities are defined as _, _, _, or _ of segments of chromosomes.

one copy of each

Diploid organisms inherit _ homologous chromosomes from the parents.

Golgi vesicles;

During cytokinesis in a plant cell, the _ come together at the former metaphase plate which fuse an form a cell plate. The cell plate grows from the center towards the cell wall and new cell walls are made.

A contractile ring; cleavage furrow

During cytokinesis in an animal cell, a _ is formed at the former metaphase plate. This pulls the equator of the cell inwards forming a crack called _ which deepens until the cells are pinched in two.

the centromeres split and the result in the sister chromatids are pulled towards each pole. ALso, certain spindle fibers begin to elongate.

During mitosis, anaphase involves _.

The arrangement of the chromosomes along the metaphase plate and the attached of the spindle fibers to each sister chromatid.

During mitosis, metaphase involves _.

The appearance of the kinetochores at the centromeres and the attachment of the spindle microtubules to those kinetochores.

During mitosis, prometaphase involves _.

the surrounding of the chromosomes (formally sister chromatids) by a nuclear envelope at each pole. Additionally, the mitotic spindle breaks down the spindle fibers push the poles further apart.

During mitosis, telophase involves _.

homeologous chromosomes are tightly paired in synapsis. From here, segments of chromosomes are exchanged in a process called crossing over which is the first source of genetic variation.

During prophase I of meiosis I, _.

Meiosis I

During which round of meiosis is genetic information mixed to create unique recombinant chromosomes.

Prophase II - condensing chromosomes Prometaphase II - microtubules attach to kinetochores of sister chromatids Metaphase II - sister chromatids align at the center of each cell Anaphase II - the sister chromatids separate Telophase II - chromosomes arrive at opposite poles and nuclear envelopes are formed around them

Explain Meiosis II.

Replication of the circular piece of DNA begins at the origin and proceeds in both directions. From there, the cells elongate and the duplicated chromosomes move to each pole. Ftsz proteins begin to form a septum in the middle of the cell that will eventually divide the cell into two identical cells.

Explain binary fission.

In prometaphase I and anaphase I, the joined chromosomes are called homologous chromosomes. In prometaphase II and anaphase II, the join chromosomes are called sister chromatids.

Explain one of the main differences between Meiosis I and Meiosis II.

Mitosis - two identical diploid cells Meiosis - four genetically distinct haploid

Explain the outcomes of Mitosis and Meiosis

four; tetards

How many sister chromatids are there after prophase? What are they called?

23

Humans are _ pairs of homologous chromosomes.

46

Humans have _ chromosomes.

single, circular DNA

In bacterial cells, the gnome consists of _ therefore cell division is simplified.

The breakdown of the nuclear envelope, condensing of the chromosomes, emergence of spindle fibers from the centrosomes, and migration of the centrosomes to the "poles" of the cell.

In mitosis, prophase involves _.

meiosis

In sexual reproduction, nuclear division is called _.

Cell growth and protein synthesis. During this phase, little change is visible as the cell is accumulating energy reserves and the chemical building blocks of DNA.

In the cell cycle, interphase G1, involves _ and _.

further growth and protein synthesis

In the cell cycle, interphase G2, involves _ and _.

DNA replication and the replication of the centrosomes. This stage leads to the formation of sister chromatids that remain firmly attached to the centromere.

In the cell cycle, interphase S, involves _ and _.

Individuals

In unicellular organisms, daughter cells are _.

1. Prophase 2. Prometaphase 3. Metaphase 4. Anaphase 5. Telophase

List the stages of mitosis.

Diploid; Haploid

Matched chromosomes are known as _, while cells that contain only one set of chromosomes are known as _.

Homologous chromosomes

Matched pairs containing genes for the same traits in identical locations along their length

Diploid; haploid

Meiosis starts with _ and ends with a _.

Karotype

Number and appearance of chromosomes

Chromatid

One half of a duplicated chromosome

Onogenes

Proto-oncogenes that are mutated become _.

only new DNA

Replication of DNA produces

mitotic

The _ phase follows interphase.

1. diploid-dominant 2. haploid-dominant 3. alternation of generations

The are three categories of life cycle:

Mitosis

The first step of the mitotic phase is _ which is further divided into stages.

Proto-oncogenes

The genes that code for the positive cell-cycle regulators

Sexual reproduction

The mechanism by which two parents combine haploid cells into diploid cells which eventually develop into an organism.

Down syndrome

The most well known example of trisomy (extraneous chromosome) is _.

Mitosis

The nuclear division during which duplicated chromosomes are segregated and distributed into daughter nuclei.

Somatic Cell

The nucleus contains two copies of each chromosome that are referred to as homologous chromosomes, referred to as "body" cells.

Mutation

The only source of variation in asexual organisms is _.

Haploid

The resulting cells from cytokinesis are _.

Genome

The total DNA content of a given cell

Mutation

The ultimate source of variation in sexual organisms _.

one round of chromosome duplication and two rounds of nuclear division

To achieve the reduction in chromosome number, meiosis consists of _ and _.

Binary fission

Type of cell division when there is no nucleus and multiple chromosomes (prokaryotes).

Nondisjunction, when sister chromatids fail to separate in meiosis

What are causes chromosome numbers abnormalities?

1. The integrity of the DNA is assessed at the G1 checkpoint 2. The proper chromosome duplication is assessed at the G2 checkpoint 3. The attachment of each kinetochore to a spindle fiber is assessed at the M checkpoint

What are the three checkpoints of the cell cycle?

G1, S, and G2

What are the three stages of interphase?

Cri-du-chat

What disease is caused by deletion of genetic material of small arm of chromosome 5?

Linked chromosomes are seperated

What happens in anaphase I of meiosis I?

The contents of the cell are separated by either the cell plate or cleavage furrow.

What happens in cytokinesis of meiosis I?

The homologous chromosomes are randomly aligned in the center of the cell called independent assortment. This is the second source of genetic variation.

What happens in metaphase I of meiosis I?

Attachment of spindle fibers to the kinetochore proteins at the centromeres occur. The nuclear membrane is gone and each tetrad is attached to microtubules from each pole to the other cell.

What happens in prometaphase I of meiosis I?

the separated chromosomes are pulled to, and arrive, at the opposite poles

What happens in telophase I of meiosis I?

This is when cells are not actively preparing to divide. In some cases, they temporarily stay here. In others, it is permanent.

What is G0 phase?

1. The genomic DNA must be replicated and then allocated into daughter cells 2. The cytoplasmic contents must also be divided to give both new cells the machinery to sustain life

What steps are essential to produce identical daughter cells?

diploid

When a cell has two complete sets of chromosomes , it is

Meiosis II

Which round of meiotic division takes place in a way that is similar to mitosis?

There would be a continual doubling in the number of the chromosome sets in every generation.

Why do diploid cells have to reduce its number of chromosome sets before fertilization can occur?

Sexual reproduction creates variation

Why is sexual reproduction so common?

Inversions

_ alter only the orientation of genes and generally have milder effects on the offspring.

Deletions and duplications

_ and _ often result in offspring with observable abnormalities.

Translocation; Schizophrenia

_ are known to have a wide range of effects, from almost none to very severe. What mental disorder is a result of this?

Homologous chromosomes

_ are matched chromosome pairs of a diploid organism.

Reciprocal translocation

_ occurs between two non-homologous chromosomes and does not cause any genetic information to be lost or duplicated.

Inversion

_ occurs when a chromosome segment breaks from the chromosome, reverses its orientation, and then reattaches in the original position.

Meiosis I

_ reduces the number of chromosome sets from two to one.