Biology Chapter 8a
The second step of binary fission is
Continued elongation of the cell and movement of the copies
At the end of the mitotic (M) phase, the cytoplasm divides in a process called
Cytokinesis
The third step in binary fission is
Division into 2 daughter cells
The first step of binary fission is
Duplication of the chromosome and separation of the copies
True of false -- a benign tumor is cancerous
False
True or False: The process of binary fisson produces two genetically identical cells in a process that requires prophase, metaphase, anaphase, telophase and cytokinesis.
False -- Eukaryotic cells duplicate through the cell cycle. Prokaryotic cells duplicate with binary fission. Binary fission process -- 3 steps 1. Duplication of the chromosome and separation of the copies 2. Continued elongation of the cell and movement of the copies 3. Division into 2 daughter cells
True of False Eukaryote cells reproduce by binary fission.
False -- Prokaryotes reproduce by binary fission; Eukaryotes by mitosis
True or false. Mitosis takes place during M phase of the cell cycle, which is longer than interphase.
False. Although mitosis takes place in M phase, M phase is shorter than interphase; cells spend most of their time in interphase.
Cells will usually divide if they receive the proper signal at a checkpoint in the _____ phase of the cell cycle.
G1
The M-phase checkpoint in mitosis determines whether sister chromatids have divided properly and there is the proper amount of DNA on each side of the dividing cell. Specifically, we would predict that this checkpoint occurs in _____ of the cell cycle.
G2
What are the 2 stages of cell cycle?
Interphase (duplication of cell contents) and Mitotic phase (division)
What makes it possible to personalize cancer treatments?
It is increasingly possible to personalize cancer treatment by • sequencing the genome of tumor cells and • tailoring treatment based upon the tumor's specific genetic profile.
At which stage of mitosis are chromosomes lined up in one plane in preparation for their separation to opposite poles of the cell?
Metaphase
The chromosomes line up in the center of the cell during which phase of mitosis?
Metaphase (Occurs in the MIDDLE of mitosis)
Spindle microtubules attach to kinetochores during
Prometaphase
In the telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in
Prophase
The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?
Prophase
What are the 5 stages of mitosis? HINT: PPMAT
Prophase Prometaphase Metaphase Anaphase Telophase
Chromosomes become visible during
Prophase, the chromatin fibers become discrete chromosomes
Living organisms produce by two methods. Which produces offspring that are similar to the parents but show variations in traits and involves inheritance of unique sets of genes from two parents.
Sexual reproduction
How do asexual and sexual reproduction differ?
Sexual reproduction can produce great variation among the offspring, whereas asexual cannot.
What is one advantage of sexual reproduction over asexual reproduction?
Sexual reproduction produces greater genetic variation than asexual reproduction. Each offspring inherits a particular combination of genes from two parents; so many combinations are possible that each offspring is essentially unique, differing from its siblings and both parents.
Cytokinesis often, but not always, accompanies
Telophase
The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?
Telophase, the final phase of mitosis.
What must happen before a cell can begin mitosis?
The chromosomes must be duplicated, which occurs during interphase.
Mitosis produces _______(how many) cell(s) that are that are _________(genetically identical/different).
two, genetically identical
What is the method of asexual reproduction?
binary fission A method of asexual reproduction by "division in half." In prokaryotes, binary fission does not involve mitosis, but in single-celled eukaryotes that undergo binary fission, mitosis is part of the process.
Bacteria divide by:
binary fission -- prokaryotes reproduce by binary fission (dividing in half)
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called _____.
chromatin
Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are
homologous chromosomes.
Nucleoli are present during
interphase
What are the reasons for cell division?
repair, easier access to nutrients, and growth of an organism
A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. There are _____ chromatids.
92
Gametes differ from somatic cells in what ways?
-They have one member of each pair of homologous chromosomes -They are haploid -They function in sexual reproduction -They have one half of the genetic material
Which of the following type of tumor can metastasize? 1.) malignant tumor 2.) benign tumor
1.) malignant tumor
A cell biologist carefully measured the quantity of DNA in grasshopper cells growing in cell culture. Cells examined during the G2 phase of the cell cycle contained 200 units of DNA. What would be the amount of DNA in one of the grasshopper daughter cells?
100 units. G2 follows S, and that during the S phase, DNA is replicated. Then, chromatids are separated during mitosis to form daughter cells.
During prophase a homologous pair of chromosomes consists of
2 chromosomes and 4 chromatids
A certain species of animal has six pairs of chromosomes. How many DNA molecules are present in the nuclei of these animals during G2 phase?
24. Each chromosome (12) is replicated, there are 24 DNA molecules in the nucleus during G2 phase.
How many steps are there in binary fission of a prokaryote cell? a.) 1 b.) 3 c.) 5
3
Which of the following checkpoints does not occur in G1? 1.) A check that growth factors are present 2.) A check that the cell is large enough for division 3.) A check that nutrients are sufficient 4.) A check that chromosome replication has been successfully completed
4.) A check that chromosome replication has been successfully completed (Chromosome replication does not occur until after G1; this checkpoint is a G2 checkpoint.)
Which of the following does NOT occur during mitosis? 1. ) condensation of the chromosomes 2.) spindle formation 3.) separation of the spindle poles 4.) separation of sister chromatids 5.) replication of the DNA
5.) replication of the DNA -- happens during interphase
What are gametes? Give an example.
A haploid reproductive cell, such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote.
What is a mass of abnormally growing cells within otherwise normal tissue?
A tumor
The phase of mitosis during which the chromosomes move toward separate poles of the cell is
Anaphase
The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?
Anaphase
Centromeres divide and sister chromosomes become full-fledged chromosomes during
Anaphase, sister chromatids separate and migrate to opposite poles
Living organisms produce by two methods. Which produces offspring that are identical to the original cell or organism and involves inheritance of all genes from one parent.
Asexual reproduction
What is the difference between a benign tumor and a malignant tumor?
Benign tumors do not metastasize (spread to other parts of the body); malignant tumors do.
True or False -- cancer cells escape controls on the cell cycle
True -- cancer cells divide excessively and invade other tissues of the body.
True or False. Mitosis and Cytokinesis together produce 2 genetically identical daughter cells; each can then go through the eukaryotic cell cycle
True. Mitosis -- division of the nucleus Cytokinesis -- division of the cytoplasm
In many organisms, including humans, chromosomes are found in homologous pairs. Homologous chromosomes are...
are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes
