BIO 101 Chapter 8 Study Guide

What are three other abnormalities that can occur in the chromosome structure?

A deletion - the loss of a chromosome segment. A duplication - the repeat of a chromosome segment, An inversion - the reversal of a chromosome segment, or

Define karyotype.

A display of micrographs of the metaphase chromosomes of a cell, arranged by size and centromere position. Karyotypes may be used to identify certain chromosomal abnormalities.

What are growth factors

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

What is the difference between asexual and sexual reproduction?

Asexual reproduction produces offspring that are identical to the original cell or organism and involves inheritance of all genes from one parent. Sexual reproduction produces offspring that are similar to the parents, but show variations in traits and involves inheritance of unique sets of genes from two parents.

How do prokaryotic cells divide? Briefly explain the process.

Binary Fission. Three stages: 1) Duplication of the chromosome and separation of the copies, 2) continued elongation of the cell and movement of the copies, and 3) division into two daughter cells.

Describe how nondisjunction can cause problems by affecting the sex chromosomes? List and describe the syndromes that can result.

Can result in abnormal numbers of sex chromosomes. Klinefelter Syndrome (male) - Have male sex organs and normal intelligence. Testes are small, individual is sterile, and has female body characteristics. Turner Syndrome (female) - Lack of a second X chromosome. Shorter, usually sterile. Needs treatment of estrogen.

What are the four categories that are used to classify tumors?

Carcinomas, Sarcomas, Leukemias, & Lymphomas.

What structure connects sister chromatids?

Centromere.

How does the chromosome number of the gametes relate to the chromosome number of the zygote?

Chromosome number of gametes is one set. Chromosome number of zygote is two sets.

What is meant by "homologus chromosomes"?

Chromosomes matched in length, centromere position, and gene locations.

What is the difference between diploid and haploid?

Diploid cells have two homologous sets of chromosomes. Haploid cells have one set of chromosomes.

How does random fertilization increase genetic variation?

Fusion of sperm and egg, each having a unique combination of chromosomes, introduces further variation.

Which stages of the cell cycle are included in interphase?

G1 Phase (first gap), The S Phase (DNA Synthesis), and G2 Phase (second gap).

What types of cells are diploid?

Humans, most plants and animals.

What types of cells are haploid?

Sperm and egg cells.

What are human gametes called?

Sperm and eggs.

Define tumor.

Abnormally growing mass of body cells that forms within otherwise normal tissue.

What is the purpose of this procedure? (karotype)

Allow for the observation of homologous chromosome pairs, chromosome number, and chromosome structure. Can be used to identify certain chromosomal abnormalities.

Define benign tumor.

An abnormal mass of cells that remains at its original site in the body.

Define malignant tumor.

An abnormal tissue mass that can spread into neighboring tissue and to other parts of the body; a cancerous tumor.

Define nondisjunction.

An accident of meiosis or mitosis in which a pair of homologous chromosomes or a pair of sister chromatids fail to separate at anaphase.

What causes Downs syndrome?

An extra copy of chromosome 21.

Define somatic cell.

Any cell in a multicellular organism except a sperm or egg cell or a cell that develops into a sperm or egg.

Make a chart for mitosis that shows the behavior of the nuclear membrane and nucleolus for each stage of mitosis, including interphase.

Interphase - Visible, chromatin duplicates in nucleus. Prophase - Nucleus/nucleolus disappears. Metaphase - Anaphase - Telophase - Nucleus/Nucleolus reappears.

Give an example of a cell that arrests in G-1. What stage is the cell said to be in?

Mature nerve cells and muscle cells. G0 Phase - Permanently non-dividing state.

Compare the phases of mitosis with the phases of meiosis.

Meiosis is followed by two consecutive cell divisions. Mitosis is followed by only one cell division.

When does independent orientation occur?

Metaphase I.

What is the difference between mitosis and cytokinesis?

Mitosis - the nucleus and its contents -most importantly, duplicated chromosomes - divide and are evenly distributed, forming two daughter nuclei. Cytokinesis - The cytoplasm is divided in two.

List the two stages in the mitotic phase of the cell cycle.

Mitosis and Cytokinesis.

What are the most prominent differences between mitosis and meiosis?

Mitosis produces two genetically identical diploid somatic daughter cells. Meiosis produces four genetically unique haploid gametes.

What kind of birth defects can result from abnormalities in chromosome structure?

Physical and mental problems. Cri Du Chat syndrome - child is mentally retarded, has a small head with unusual facial features, and has a cry that sounds like the mewing of a cat.

In what stage of the cell cycle is the sister chromatids produced?

Prophase

When does crossing over occur?

Prophase I of meiosis.

What are some important roles of cell division in organisms?

Reproduction of single-celled organisms, growth of multicellular organisms from a fertilized egg into an adult, repair and replacement of cells, and sperm and egg production.

How are chromatin and chromosomes the same? How are they different?

Same: Contain DNA. Different: Chromatin is too thin to be seen by a light microscope. Chromosomes are visible under a light microscope.

What is the difference between autosomes and sex chromosomes?

Sex chromosomes X and Y differ in size and genetic composition. Autosomes are other 22 pairs of chromosomes have the same size and genetic composition.

Define locus.

The particular site where a gene is found on a chromosome. Homologous chromosomes have corresponding gene loci.

What is meant by random fertilization?

The random combination of chromosomes resulting from pairing up 1 of the 8.4 million possible chromosome combinations of a sperm with 1 of the 8.4 million possibly chromosome combinations of the egg (due to independent assortment of chromosomes during Meiosis. This comes out to about 70 trillion combinations, which does not even factor in the crossing over of genetic material during Meiosis.

What is metastasis?

The spread of cancer cells beyond their original site.

How does independent orientation increase genetic variation in offspring?

There is an equal probability of the maternal or paternal chromosome facing a given pole. The number of combinations for chromosomes packaged into gametes is 2n where n=haploid number of chromosomes.

What is a sister chromatid?

Two copies of a chromosome that contains identical copies of DNA.

Does crossing over increase genetic variation of independent orientation?

Yes.

When gametes fuse together, what is the resulting cell termed?

Zygote.

What is a gamete?

A sex cell; a haploid egg or sperm. The union of two gametes of opposite sex (fertilization) produces a zygote.

Compare and contrast mitosis in plant versus animal cells. Include structures that are unique to one cell type or the other. Emphasize the differences in cytokinesis.

In animal cells, cytokinesis occurs by a process known as cleavage. The first sign of cleavage is the appearance of a cleavage furrow. A cleavage furrow forms from a contracting ring of microfilaments, interacting with myosin.The cleavage furrow deepens and eventually pinches the parent cell in two, producing two completely separate daughter cells, each with its own nucleus and share of cytoplasm. In plant cells, during telophase, membranous vesicles contain cell wall material collect at the middle of the parent cell. The vesicles fuse, forming a membranous disk called the cell plate. The cell plate forms outward accumulating more cell wall materials as more vesicles fuse with it. Eventually, the membrane of the cell plate fuses with the plasma membrane, and the cell plate's contents join the parental cell wall. The result is two daughter cells, each bounded by its own plasma membrane and cell wall.

List the stages of the cell cycle and describe cell activity during each stage. List the 2 stages in the Mitotic Phase.

Interphase (growing stage) - the cell roughly doubles everything in its cytoplasm and precisely replicates its chromosomal DNA. Makes more cytoplasm. Increases its supply of proteins, creates more cytoplasmic organelles. Chromosomes duplicate in this period. Mitotic Phase (cell division) - The cell actually divides. In mitosis, nucleus and its contents are equally distributed, forming two daughter nuclei. In cytokinesis, cytoplasm is divided in two. Mitosis and Cytokinesis

Make a chart for mitosis that shows the behavior of the spindle for each stage of mitosis, including interphase.

Interphase - Prophase - Spindle forms. Metaphase - Spindle is fully formed. Anaphase - Telophase - Spindle disappears

Make a chart for mitosis that shows the behavior of chromosomes for each stage of mitosis, including interphase.

Interphase - Chromosomes duplicate. Prophase - Chromatin coils to form chromosomes. Chromosomes become visible. Metaphase - Chromosomes line up along the metaphase plate. Anaphase - Chromatids separate and are pulled towards the poles. Telophase - Chromatin fiber of each chromosome uncoils.

Make a chart for mitosis that shows the behavior of centrosomes for each stage of mitosis, including interphase.

Interphase - Two centrosomes form. Prophase - Microtubles emerging from the centrosomes at the poles of the mitotic spindle reach the chromosomes. Metaphase - Anaphase - Telophase -

What is the function of checkpoints in the cell cycle?

Stop an event or signal an event to proceed.

In what stage does cytokinesis occur?

Telophase.

What are the special terms associated with the chromosomes in metaphase I of meiosis?

Tetrads.

What is chromosomal translocation?

The attachment of a segment to a non-homologous chromosome that can be reciprocal.