Exam 3: Chapter 10 Cell Reproduction Study Guide
What is G0 and what are three reasons cells enter G0?
(quiescence) cell is neither dividing, nor preparing to divide- occurs outside of the cell cycle 1) no need for more of that cell 2) the cell is damaged 3) terminally differentiated-already fated; has chosen its final state.
How do homologous chromosomes differ from sister chromatids?
-homologous chromosomes are the two chromosomes that make a chromosome pair. -A sister chromatid is the duplicate of each pair of homolous chromosomes.
How does meiosis contribute to the human life cycle?
-produces ethically diverse gametes -only happens in gonads (testes/ovum)
What is the centromere? What is its function?
-the region of a chromosome where microtubules of the spindle attach and joins sister chromatids together
Complete the table below. At each stage, draw a picture of a cell at that stage that has 4 chromosomes (2 pairs).
Prophase: -chromosomes condense -spindle apparatus assembles -2 centrioles move to opposite poles forming spindle apparatus -nuclear envelope breaks down (golgi and ER disperse) Prometaphase:- -spindle fibers are fully attached to chromosomes -chromosomes begin to move to the center of the cell Metaphase- -spindle fibers align chromosomes at the equator of the cell (metaphase plate) -chromosomes align single file Anaphase- -cohesion molecule that hold the chromosomes together is degraded by an enzyme called seperase -sister chromatids are pulled to opposite poles of the cell by the spindle fibers Telophase- -spindle fibers dissemble -nuclear envelope forms around each set of chromosomes -chromosomes begin to de-condense, Golgi and ER reform
Definition: The chromosomes decondense and the nuclear envelope reforms.
Telophase
How are homologous chromosomes alike?
They are the same size They contain the same genes
Fill in the blanks
Top: Haploid Gametes Right (1st): Fertilization Right (2nd): Zygote Right (3rd): Mitosis Left (bottom): Multicellular Diploid Left (top): Meiosis
What are 5 ways a cancer cell differs from a normal cell?
1) cell becomes immortal, divides forever 2) damage to cell junctions-spreading 3) have an unusual # of chromosomes 4) have changes in shape 5) grow their own blood vessels
If a cell has 8 pairs of chromosomes, what is the diploid and haploid number of this organism?
16 diploid 8 haploid
At the end of mitosis, how many daughter cells are produced? Are they diploid or haploid? Are they identical or different?
2 daughter cells that are diploid and they are identical
What is the haploid (n) number in humans?
23 chromosomes
At the end of S phase, how many chromosomes will be present in the nucleus of a human?
4 chromosomes
What is the diploid (2n) number of humans?
46 chromosomes
In the human, the body cells (non-sex cells) contain two sets of chromosomes totaling
46.
At the end of S phase, how many chromatids will be present in the nucleus of a human somatic cell?
8 chromatids
In the following picture, which letter indicates homologous chromosomes. Type the letter in the blank provided
A
What is a cell cycle checkpoint?
A control point in the cell cycle where stop and go-ahead signals can regulate the cycle and make sure that everything is going well
What are homologous chromosomes? How are they similar? How are they different?
A pair of chromosomes pairs (one from each parent) that are similar in size and genes different: alleles (1 from mom 1 from dad)
The sister chromatids are moving to the opposite poles
Anaphase
In the following picture, which letter indicates a centromere. Type the letter in the blank provided
D
All cells in the human are undergoing cell division. True or False?
False
Cancer results when a cell has an inactive oncogene and an overactive tumor suppressor gene. True or False?
False
What is a gene and what does it encode?
Functional units of DNA that code for RNA and proteins
The primary growth phase of a cell is
G1 phase
There are 3 important checkpoints in the cell cycle. What is the purpose of each of the following checkpoints? a. G1 checkpoint: b. G2 checkpoint: c. Metaphase checkpoint:
G1: -assessing if ready to replicate chromosomes -are cells large enough to divide? -is there enough energy and proteins to form chromosomes G2: -checking to ensure all DNA was replicated properly -checking if the cell is ready for mitosis -checks to see if chromosomes are replicated correctly Metaphase checkpoint- -checking accuracy of mitosis-spindle checkpoint -assessing if all chromosomes are attached to spindle fibers (move them around; non-disjunction)
The cell cycle is divided into three main phases, interphase, mitosis, and cytokinesis. Most of the cell cycle is spent in Interphase. Interphase can be subdivided into 3 subphases. What happens in each of these sub-phases: A: G1 B: S C: G2
G1: cell growth and repair of chromosomes S: chromosomes replicate each other and each contain 2 sister chromatids G2: cell prepares for mitosis & cytokinesis
Which phase of Interphase occurs after DNA replication and is a time where the cell creates energy and proteins to prepare for mitosis
G2
Meiosis is another type of cell division in which the chromosomes replicates once but the cell undergoes two rounds of cell division. Explain why this is important to the function of meiosis.
In meiosis, it is important that we reduce the amount of DNA by half, so that when the gametes come together the zygote will have a complete set of chromosomes. The chromsomes number is reduced by half after meiosis I and the number of chromatids is reduced after meiosis II. Response Feedback: This is for reduction of chromosomes, not genetic diversity.
What are the roles of the following genes in control of the cell cycle? a. proto-oncogene b. Tumor suppressor gene
a: proto-oncogene: normal genes that cause the cells to divide (before cancer) b: tumor suppressor gene- signals normal genes to stop cell division (if something is wrong) similar to a brake pedal
What is a genome?
all of the genetic material in a cell
The control of cellular number is a balance between which two cellular processes?
balancing apoptosis and mitosis
When a proto-oncogene becomes mutated, it is called an oncogene. How does this mutation contribute to the development of cancer?
cells would divide without stopping
The chromosomes are aligned in the middle of the cell
Metaphase
Begins when the nuclear envelope has disappeared. The chromosomes are attached to the spindle fibers and are moving towards the middle of the cell.
Prometaphase
The chromosomes begin to condense and the spindle fibers begin to form.
Prophase
How is DNA organized in cellular genomes?
chromosomes
Which of the following describes the shape and location of prokaryotic chromosomes?
circular chromosome in the nucleoid region
The proteins that participate in the functioning of the checkpoints for cell cycle control are
cyclins and cyclin-dependent kinases
Explain the difference between cytokinesis in animal cells and plant cells.
cytokinesis in plant cells leads to a cell plate that results in the division of cell wall and it leads to a cleavage furrow in animal cells.
The division of cytoplasmic material into the two daughter cells is called
cytokinesis.
A mutated tumor suppressor gene results in:
damage cells dividing out of control
What is difference between the diploid and haploid of a eukaryotic cell?
diploid is a complete set of chromosomes n=46 haploid- 1 of each pairs, half of the diploid n=23
What is the function of cyclins/Cyclin dependent kinases in the regulation of the cell cycle?
enzymes that add phosphates to other molecules paired with cyclin that controls the cell cycle checkpoints.
Animal cells typically achieve cytokinesis by
forming a cleavage furrow that pinches the cell into two
Cancer results from genetic mutations. What is a genetic mutation? Which types of genes are mutated?
gene mutations- change in DNA sequence of a gene types of genes mutated- a cancer gene is the mutated proto-oncogene
How does mitosis contribute to the human life cycle?
growth repair regeneration
If a eukaryotic cell has a single set of chromosomes, it is called
haploid
Why is cell cycle control important?
it is important for growth, repair of cells and regeneration
Which of the following describes the shape and location of eukaryotic chromosomes?
linear chromosomes in the nucleus
The framework of microtubules that appears in cell division which eventually moves the chromatids apart is called the
mitotic spindle- a protein fibers that attach to the chromosomes at the centromere.
What is the function of the mitotic spindles in cell division?
protein fibers that attach to chromosomes at the centromeres and move chromosomes during cell division.
What is a growth factor? How does it affect the cell cycle?
protein ligands (chemicals) released by neighboring cells and tells to divide and begin the cell cycle
What is the function of the kinetochore in cell division?
protein that links the spindle fibers to the centromeres of the chromosomes.
What is the cell cycle?
sequence of events that describes the stages of a cell's life until the cell divides and becomes two new cells.
Fill in this table comparing the genomes of prokaryotes and eukaryotes.
shape (pro) circular (eukaryote) linear # of Chromosomes (pro) 1 (Eukaryote) 46 Location of genome: (pro) nucleoid region (eukaryote) nucleus
How does a mutation of a tumor-suppressor gene result in cancer?
the mutation stops tumor suppression gene (like removing a brake) and the cell continues to divide and grow out of control and mutations pass on to the next generation.
What is the function of centrioles in animal cell division?
to form spindle fibers (protein fibers made of microtubules) attached to chromosomes
In the following picture, how many chromosomes are pictured. Type the number in the blank provided
two
Cancer is:
uncontrolled cell division that results in an excess of cells
What is cancer?
uncontrolled cell growth that results in the damage of normal tissue and body functions and can spread (metastisize)
