genetics and cell division chapter 9

mitotic phase

(M Phase) that portion of the cell cycle that includes both mitosis and cytokinesis. mitosis is the separation of a somatic cell's duplicated chromosomes; cytokinesis is the physical separation of one cell into two daughter cells

Prophase has begun when: A. well-defined chromosomes are distinguishable B. a cleavage furrow has formed C. chromosomes have aligned along the metaphase plate. D. chromosomes have duplicated E. sister chromatids have separated

A

chromatin

A molecular complete of DNA and its associated proteins that make up the chromosomes of eukaryotic organisms.

The average length of the cell cycle in animal cell is about: A. 16 hours B. 30 minutes C. 2 hours D. 12 hours

B

If a cell is not dividing and has not yet replicated its DNA (duplicated its chromosomes), what phase of the cell cycle would it be in? A. gap-two (G2) phase B. synthesis (S) phase C. gap-one (G1) phase D. prophase E. mitotic phase

C

The cell cycle is linked to cancer because cancer always entails: A. too much time is spent in S phase. B. a slow-down in mitosis C. unrestrained cell division D. a misalignment of chromosomes E. not enough time spent in M phase

C

A gene can be described as: A. a protein that contains enough information to carry out a task. B. a hormone that prompts some action inside a cell. C. a series of DNA bases that transfer energy within a cell D. a series of DNA bases that contain information for production of a protein. E. a protein that delivers information to a ribosome.

D

The four bases found along the DNA double-helix are: A. adenine, thymine, guanine, and cytosol. B.adenine, thyroxine, glucose, and cytosine. C. adrenaline, thymine, glucosamine, and uracil. D. adrenaline, thymine, guanine, and cytosine. E. none of the above

D

In what way does DNA help form and then maintain our bodies?

DNA contains information for the production of proteins. These proteins are "workers" and building blocks that serve a vast array of functions in organisms such as ourselves. Through the work of proteins, our bodies develop and carry out everyday functions.

Proteins serve in living things as: A. hormones B. enzymes C. cell receptors D. structural building blocks E. all of the above

E

The human genome contains: A. 23 pairs of chromosomes B. 48 chromosomes C. as many as 25,000 genes D. b and c, above E. a and c, above

E

How do mitosis and cytokinesis differ?

Mitosis serves to equally divide a cell's genetic material into two portions of a parent cell that will become daughter cells. Cytokenisis is the physical separation of a parent cell into two daughter cells.

Name the four phases of mitosis and describe the major events occurring in each phase.

Prophase- Duplicated chromosomes condense and become visible; the centrosome duplicates and centrosomes migrate to the poles; the nuclear membrane breaks down; and the mitotic spindle if formed Metaphase-chromosomes pairs align along the cell midline or metaphase plate and attach to the microtubules extending from the cellular poles. Anaphase- the sister chromatids paired along the metaphase plate separate and then migrate to the two poles of the cell Telophase- the condensed chromosomes unwind at their respective poles, and new nuclear membranes are formed around the chromosomes. At this point, division of genetic material is complete. the cell is ready for cytogenesis.

centrosome

a cellular structure that acts as a organizing center for the assembly of microtubules. A cell's centrosome duplicates prior to mitosis and plays an important part in the development of the cell's mitotic spindle

karyotype

a pictorial arrangement of a full set of an organism's chromosomes.

metaphase plate

a plane located midway between the poles of a dividing cell

The protein synthesis pathway --- DNA ----> mRNA ----> protein--- is a very important concept in biology. Within this framework: A. What are the information- bearing "building blocks" of DNA? B. Where is DNA located in the cell? C. What does the "m" in mRNA stand for? D. Using this knowledge, what is the function of mRNA, and where is it used? E. What are the building blocks of proteins? F. Where does protein formation occur?

a.) four different bases-adenine,thymine,guanine, and cytosine, or A, T, G, and C, respectively b.) in the nucleus c.) messenger d.) mRNA is used as a cellular messenger, DNA's information is copied onto it in the nucleus, after which it carries this information to the cytoplasm, where the information is used within ribosomes to put together sequences of amino acids that form proteins e.) amino acids f.) in ribosomes residing in the cytoplasm

Proteins are made up of a set of building blocks called ________. In any given protein, the order of these buildings blocks is specified by the order of the _______ that make up a _________.

amino acids, bases, gene

homologous chromosomes

chromosomes that are the same in function and hence size. species that are diploid (have two sets of chromosomes) have matching pairs of homologous chromosomes; one member of each homologous pair is inherited form the male, the second member of each homologous pair is inherited from the female.

Cell division has two separable components: Mitosis is the movement of the cell's _______ into opposing parts of the cell, while cytogenesis is the physical separation of one cell into two________.

chromosomes, daughter cells

Owing to their cell wall, plants cells cannot carry out _______ in the same way that animal cells do. Thus, plant cells build a new ________ and _______ that run roughly down the middle of the parent cell, creating two daughter cells that then separate.

cytokinesis, cell wall, plasma membrane

In human beings (and many other organisms) chromosomes come in pairs that are said to be _______, meaning the same in function. The pairs rule in seen in women, who have a pair of chromosomes that confer female gender, the _________ chromosomes. Meanwhile, men have one _______ chromosomes (like women) but one ________ chromosomes, which confers the male gender.

homologous, X, X, Y

Proteins are produced by means of information encoded in DNA begin copied onto a molecule called ________, which then ferries the information toa structure called a ________. At this structure, _________ are linked to one another in the order specified by the _______, thus resulting in a _______.

messenger RNA (mRNA), ribosomes, amino acids, mRNA bases, protein

Mitosis and cytogenesis take place in the relatively short _______ phase of the cell cycle. Meanwhile, a typical cell spends most of its time in the cycle's ________, carrying out its normal function and duplicating its chromosomes in preparation for division.

mitotic, interphase

Bacterial cells are prokaryotes, meaning their cells have no ______. In the cell division, a bacterial cell's single chromosome duplicates and the resulting daughter chromosomes attach to different sites on the ________, after which the cell divides in two. This process is known as ________.

nucleus, plasma membrane, binary fission

chromatid

one of the two identical strands of chromatin (DNA plus associated proteins) that make up a chromosome in its duplicated state

Compared to animal cells, what additional cell structure must plant cells deal with when they are undergoing cytokinesis? Given this difference, how do plant cells carry out cytokinesis?

plant cells have cell walls, while animal cells do not. In plant cells, membrane-lined vesicles, filled with a complex sugar, migrate to an area near the metaphase plate and begin fusing together, eventually forming a cell plate that runs from one side of the parent cell to the other. The membrane portion of the plate fuses with the original parent-cell plasma membrane, thus dividing the parent cell in half via formation of two new plasma membranes. the material inside the cell-plate membrane then forms the foundation of the new cell walls of the daughter cells.

Genes contain information for the production of _______. The building blocks of genes are a set of four ________ whose symbols are _________, _______, _______, and ________.

proteins, bases, A, T, G , C

Chromosomes are composed of both DNA and its associated _______. In duplicated state, each chromosomes is composed of two identical ________.

proteins, sister chromatids

For any cell to divide, the DNA it contains must first double or _______ so that both of the daughter cells that are produced will have their own complement of DNA. To look at this process another way, prior to cell division each of the chromosomes in a cell must _____.

replicate, duplicate

In mitosis, the apportioning of DNA comes about through the separation of _______, each of which then becomes a fully functional _______ in one of the newly formed daughter cells.

sister chromatids, chromosomes

chromosome

structural unit containing part or all of an organisms genome, consisting of DNA and its associated proteins (chromatin). The human genome is made up of 23 pair of chromosomes, or 46 chromosomes in all.

In what way are the 23 pairs of human chromosomes "matched" pairs of chromosomes?

the 23 pairs of human chromosomes are matched ( or homologous) in the sense that the two members of each pair contain information about similar functions, such as hair color, metabolic processes, and so forth. the one exception to the matched-pair rule comes in human males, who have 22 pairs of matched chromosomes, but then one X chromosomes and one Y chromosomes, which are not matched. Human females have 23 matched pairs, including two X chromosomes.

genome

the complete makeup of an organism's genetic information. More narrowly, the complete haploid set of an organism's chromosomes.

Binary fission

the form of reproduction carried out by prokatyotic cells in which the chromosome replicates and the cell pinches between the attachment points of the two resulting chromosomes to form two new cells

microtubule

the largest of the cytoskeletal filaments, microtubules take the form of hollow tubes composed of the protein tubulin. they help give structure to the cell, serve as the "rails" on which transport vesicles move,and form the cellular extensions known as cilia and flagella

mitotic spindle

the microtubules active in cell division, including those that align and move the chromosomes.

cytokinesis

the physical separation of one cell into two daughter cells

interphase

the portion of the cell cycle in which the cell simultaneously carries our its works and- in preparation for division - duplicates it'd chromosomes. the other primary phase of the cell cycle is mitotic phase ( or M phase), which includes both mitosis (in somatic cells) and cytokinesis.

cell cycle

the relatively thick layer of material that forms the periphery of all plant and fungal cells and many types of bacterial, archael, and protist cells

mitosis

the separation of a somatic cell's duplicated chromosomes prior to cytokinesis.

genetics

the study of physical inheritance among living things.