e. cell cycle check your learning

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CHECK YOUR LEARNING

Cell Cycle, Cell Division

What does a eukaryotic genome look like?

A) One circular molecule (chromosome) of DNA and sometimes some additional small pieces called plasmids.

B) Pairs of linear chromosomes organized in a nucleus.

C) Pairs of linear chromosomes organized at a nucleoid.

D) All of an organism’s genetic information.

Which terms (in the order given) below are the best choice for filling in the blanks in the following sentence?

Human body (somatic) cells have _____ chromosomes organized in ____ pairs. These somatic cells are ____________. Human gametes (egg and sperm) have ________ chromosomes and are referred to as being __________.

A) 46, linear, haploid, 23, diploid

B) 23, linear, haploid, 46, diploid.

C) 46, linear, diploid, 23, haploid

D) 46, circular, diploid, 23, haploid

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Cell Reproduction

Which of the following about homologous chromosomes is true?

A) The genes on homologous chromosomes are identical.

B) X and Y are the only identical homologous chromosomes.

C) Each copy of a homologous pair comes from the same parent.

D) The genes of homologous chromosomes are found at the same locus.

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Cell Reproduction

Which of the following about homologous chromosomes is true?

A) The genes on homologous chromosomes are identical.

B) X and Y are the only identical homologous chromosomes.

C) Each copy of a homologous pair comes from the same parent.

D) The genes of homologous chromosomes are found at the same locus.

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Cell Reproduction

A human sperm cell has how many chromosomes?

A) 12

B) 23

C) 46

D) 14

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Cell Reproduction

A human sperm cell has how many chromosomes?

A) 12

B) 23

C) 46

D) 14


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Why do organisms need to undergo cell division?

A) Growth of the organism (multicellular organisms)

B) Reproduction (unicellular organisms)

C) Repair of cells and tissues

D) All of the above


Cell Reproduction

How does the genome of a diploid organism ensure that it does not have exactly the same traits as another organism?

A) The chromosomes are able to circularize, forming new combinations of genes

B) The genome is packaged into chromosome pairs, with each member of a pair inherited from a parent

C) The blood type of an organism defines its traits

D) All X and Y chromosomes are different and control the unique characteristics of an organism

What is the major purpose of DNA compaction?

A) To allow DNA to fit into the cell, especially during times where the DNA is replicated (preceding mitosis or meiosis).

B) To allow for better use of genes.

C) To ensure that genes are not lost.

D) To allow for more efficient aerobic respiration.

During DNA compaction the nucleosomes form “beads on a string” of DNA, and between the beads are linker DNA. These coil further into 30 nm diameter fibers referred to as _______________.

A) histones

B) scaffolds

C) chromatids

D) chromatin

During DNA compaction the DNA is wound around histone proteins to form a structure called a nucleosome. How many histone proteins are in each nucleosome?

A) one

B) four

C) eight

D) ten

Define each of these terms:

cell cyclecentromerechromatiddiploidgametegenegenomehaploidhistonehomologous chromosomeslocusNucleosome

Answers are in your reading.


Cell Reproduction

If cellular division in an organism were to cease, which of the following would occur?

A) The organism would be unable to replace dying or damaged cells.

B) The organism would have to rely on asexual reproduction.

C) The organism would have to rely on sexual reproduction.

D) all of these answers

What is the cell cycle?

A) Production of gametes.

B) An ordered sequence of events that a cell passes through between one cell division and the next.

C) Growth of an organism.

D) All of the above

Just to be clear.....the cell cycle as described in your readings is something that cells do only when they are undergoing cell division! When they are not actively dividing, then they enter a stage called Go where the cell cycle is arrested. Cells are still metabolically active in Go, they just aren’t actively dividing. Cell division only happens when organisms need it to. Remember – uncontrolled cell division is a problem (think tumor cells). Nerve cells for example, stay in Go once they reach maturity, and typically never enter the cell cycle again.


Cell Reproduction

Chromosomes are duplicated during what stage of the cell cycle?

A) S phase

B) G1 phase

C) all of these answers

D) G2 phase

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Cell Reproduction

Chromosomes are duplicated during what stage of the cell cycle?

A) S phase

B) G1 phase

C) all of these answers

D) G2 phase



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Which of the following has the correct labels for A, B and C?

A) A = meiotic phase, B = meiosis, C = cytokinesis

B) A = mitotic phase, B = meiosis, C = cytokinesis

C) A = mitotic phase, B = mitosis, C = cytokinesis

D) A = mitotic phase, B = mitosis, C = karyokinesis

Which of the following is the correct order of events in mitosis?

A.

BC

What is the purpose of mitosis?

A) To ensure correct cell division takes place.

B) To form gametes.

C) To ensure DNA synthesis is accurate.

D) To ensure each new daughter cell resulting from cell division has an identical nucleus (nuclear division).

Which of the following is the correct order of events in mitosis?

A) Sister chromatids line up at the metaphase plate. The kinetochore becomes attached to the mitotic spindle. The nucleus reforms and the cell divides. Cohesin proteins break down and the sister chromatids separate.

B) The kinetochore becomes attached to the mitotic spindle. Cohesin proteins break down and the sister chromatids separate. Sister chromatids line up at the metaphase plate. The nucleus reforms and the cell divides..

C) The kinetochore becomes attached to the cohesin proteins. Sister chromatids line up at the metaphase plate. The kinetochore breaks down and the sister chromatids separate. The nucleus reforms and the cell divides.

D) The kinetochore becomes attached to the mitotic spindle. Sister chromatids line up at the metaphase plate. Cohesin proteins break down and the sister chromatids separate. The nucleus reforms and the cell divides.


Cell Reproduction

The drug colchicine inhibits the formation of spindle fibers. If you treat dividing cells with colchicine, what would you expect the result to be?

A) The cells would be unable to divide and eventually die.

B) The sister chromatids would all segregate to the same daughter cell.

C) The chromosomes would segregate randomly into each daughter cell.

D) The chromosomes would line up along the metaphase plate but not separate.


Cell Reproduction

The mitotic spindles arise from which cell structure?

A) centromere

B) kinetochore

C) cleavage furrow

D) centrosome


Cell Reproduction

What do you predict would happen if only one microtubule attatched to a pair of sister chromatids during mitosis?

A) The sister chromatids would fail to separate and be pulled to the same pole.

B) The sister chromatids would become tangled and break during separation.

C) The sister chromatids would separate normally.

D) Cellular division would be arrested.


Cell Reproduction

Attachment of the mitotic spindle fibers to the kinetochores is a characteristic of which stage of mitosis?

A) prophase

B) metaphase

C) anaphase

D) prometaphase


Cell Reproduction

Which of the following events occurs during the prophase stage of mitosis?

A) The cell grows in size.

B) The cell membrane pinches off and splits into two daughter cells.

C) Identical chromosomes align themselves along the equator of the cell.

D) The nuclear membrane disappears


Cell Reproduction

Which of the following statements about the products of a single diploid cell that has gone through mitosis is true?

A) One diploid cell will have formed two genetically diverse cells.

B) One diploid cell will have formed four separate cells.

C) One diploid cell will have formed three separate cells.

D) One diploid cell will have formed two identical diploid cells.


Cell Reproduction

Identical copies of chromatin held together by cohesin at the centromere are called _____.

A) histones

B) nucleosomes

C) chromatin

D) sister chromatids

e. cell cycle check your learning

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