Mitosis and Meiosis, Chapter 12 & 13

What happens during Cytokinesis in animal cells and plant cells?

animal: cleavage furrow, two cells are made plant: cell wall forms separating the two new nuclei and creating two cells

Define chiasmata?

area where crossover occurs

What organisms typically use a haplontic life cycle?

most fungi, and some protists

Where is a bacterial cell's DNA found?

nucleoid region

Ribosomes are manufactured by what?

nucleolus

What organisms typically use alternation of generations life cycle?

plants and some algae

The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell.

plasma membrane

Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle?

G1

A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain?

92

How many chromosomes are in a cell with 6 sister chromatids and 3 centromeres?

1-1, 1-1, 1-1 3 chromosomes

If an organism has 36 chromosomes and undergoes meiosis, how many chromosomes appear in each of the daughter cells?

18 chromosomes

What are centrosomes comprised of? What types of cells are they found in?

2 centrioles organizing microtubules 9 sets, 3 microtubules each animal cells only

Mitosis results in the formation of how many cells of what kind? Meiosis results in the formation of how many cells of what kind?

2 diploid cells 4 haploid cells

What is the result of mitosis?

2 identical diploid daughter cells

What is the result of meiosis?

4 genetically different haploid daughter cells

What number and types of chromosomes are found in a human somatic cell? (autosomes)

44 autosomes and 2 sex chromosomes

Duuring G1, each liver cell contains 46 chromosomes in its nucleus. How many chromosomes go to each spindle pole during MITOSIS?

46 chromosomes or 23 homologous pairs

How much of mitosis is interphase?

90%

What causes the cleavage furrow in animal cells during cytokinesis?

Actin filaments due to motor protein myosin = microfilaments

What causes a Cleavage Furrow?

Actin-myosin fibers (microfilaments) form a ring around the middle of the cell to cleave it in two

Protein kinases are enzymes that activate or inactivate other proteins. How do they do this?

Phosphorylation

The presence of a cell wall prevents the cell from dividing by constriction. True or false for Bacteria, Plants, and Animals.

B-false A-false P-true

Tubulin or tubulin-like molecules function in binary fission (in bacteria) or cytokinesis (in animals and plants). True or false for Bacteria, Plants, and Animals.

B-true A-false P-true

Cells divide by constriction of a ring of protein. True or false for Bacteria, Plants, and Animals.

B-true A-true P-false

What is the name of cell division for prokaryotes?

Binary fission

Cytochalasin B is a chemical that disrupts microfilament formation. How would this interfere with cell division?

Cleavage In animal cells, the cleavage furrow forms when a ring of microfilaments contracts, causing the parent cell to be pinched in two.

Anaphase

Cohesion proteins break down and sister chromatids separate. Kinetochore microtubules shorten, pulling the chromosomes to opposite ends of the cell

Define Aneuploidy.

an abnormal number of chromosomes

Metaphase

Centromeres become aligned in a plane in the center of the cell called the "metaphase plate"

Name 2 things that happen during prophase?

Chromatin condenses Nucleoli disappear Mitotic spindle begins to form Centrosomes move away from each other

G2 of Interphase

Chromosomes are duplicated but not highly condensed

What happens in each stage of interphase?

G1- immediately after cell division S phase- DNA synthesis G2- metabolic activity and growth

_____ are surface appendages that allow a bacterium to stick to a surface.

Fimbriae

What is chromatin composed of?

DNA and protein

When does cyclin levels decrease? Increase?

During G1, the degradation of cyclin continues, and the Cdk component of MPF is recycled. Cyclin combines with Cdk, producing MPF. When enough MPF molecules accumulate, the cell passes the G2 checkpoint and begins mitosis. Accumulation starts late S phase.

What structure stores, modifies, and packages products of the ER?

Golgi Apparatus

What organisms typically use a diplontic life cycle?

Humans, most animals

Where do microtubules connect on chromosomes?

Kinetochore

Compare and contrast mitosis and meiosis.

Meiosis becomes 4 genetically different haploid (gametes) while mitosis gives 2 identical diploid

What are the two types of cell division for eukaryotes?

Mitosis and Meiosis

Telophase

Nuclear envelope and nucleoli re-form. Chromosomes become less condensed. Spindle disappears. Cytokinesis typically begins.

Prometaphase

Nuclear envelope breaks down. Kinetochores form on centromeres, and attach to some spindle microtubules.

Name 2 things that happen during metaphase?

Nuclear envelope dissolves Chromosomes line up along metaphase plate Centrosomes are on opposite poles of the cell Kinetochores of sister chromatids are attached to kinetochores of microtubules

Name 2 things that happen during telophase?

Nuclear envelopes form around each of the two sets of chromosomes Chromosomes become less condensed There are two identical nuclei

Prophase

Nucleolus disappears. Chromatin condenses so much that individual chromosomes become visible. Microtubules grow from centrosomes to form asters and mitotic spindle. Centrosomes move toward ends of cell.

Compare and contrast DNA replication in prokaryotes and eukaryotic cells.

Similarities: a. both extremely accurate ~1 error per 10^9 nucleotides b. leads to chromosomes having 2 DNA molecules (sister chromatids) c. DNA structure is the same, 2 DNA strands Differences: a. prokaryote's replication must start at its only origin. Eukaryotes have many origins, start replication wherever b. eukaryotes have checkpoints

Compare and contrast potential reproductive signals in prokaryotes and eukaryotic cells.

Similarities: a. conditions are good b. always a parent cell that divides c. equal division of chromosomes d. daughter cells identical to parent cell Differences: Prokaryotes- a. size b. conditions ie. food, temp, etc Eukaryotes- a. based on needs of the organism ...environments are different

Name 1 thing that happen during anaphase?

Two sister chromatids are torn apart and pulled to opposite sides of the cells Michrotubules (spindle fibers) shorten

If a eukaryotic cell is in the G1 phase of the cell cycle, which statement about the cell's chromosomes must be correct? a. Each chromosome is made of a complex of DNA and associated proteins. b. Each chromosome consists of two identical chromatids. c. The chromosomes are preparing for DNA synthesis.

a. Each chromosome is made of a complex of DNA and associated proteins.

What are the four events that must occur during cell division?

a. a reproductive signal b. replication of DNA c. segregation d. cytokinesis

Asexual reproduction _____. a. produces offspring genetically identical to the parent b. is limited to single-cell organisms c. is limited to plants d. leads to a loss of genetic material e. requires both meiosis and mitosis

a. produces offspring genetically identical to the parent

What are somatic cells?

all body cells except the reproductive cells; 44 autosomes

Which statement provides the best description of the interphase portion of the cell cycle? a. Interphase is a resting stage prior to cell division. b. During interphase, a cell is metabolically active. c. Interphase is a brief period between mitosis and chromosome duplication.

b. During interphase, a cell is metabolically active.

Which of the following occurs during meiosis but not during mitosis? a. Chromosomes migrate to opposite poles. b. Synapsis occurs. c. Chromosomes align at the metaphase plate. d. Chromosomes condense. e. A spindle apparatus forms.

b. Synapsis occurs

Which of the following is true of kinetochores? a. They attach to the ring of actin along the cytoplasmic surface of the plasma membrane, causing the actin to contract to form the cleavage furrow. b. They are sites at which microtubules attach to chromosomes. c. They are the primary centromere structures that maintain the attachment of the sister chromatids prior to mitosis. d. They are located at the center of the centrosome; their function is to organize tubulin into elongated bundles called spindle fibers. e. They interdigitate at the cell's equator and then move apart, causing the cell to elongate.

b. They are sites at which microtubules attach to chromosomes.

Which of the following does not occur during mitosis? a. separation of the spindle poles b. replication of the DNA c. spindle formation d. condensation of the chromosomes e. separation of sister chromatids

b. replication of the DNA

What are the differences and similarities between synapsis and crossover?

both occur in prophase I of Meiosis I, Synapsis: duplicated chromosome pairs line up and physically attach like a zipper

Which of the following correctly matches a phase of the cell cycle with its description? a. M: duplication of DNA b. S: immediately precedes cell division c. G1: follows cell division d. G2: cell division e. All of the above are correctly matched.

c. G1: follows cell division

Which of the following is NOT true of eukaryotes: a. Eukaryotes are defined by having a nucleus b. Animal cells differ from plant cells in that animal cells do not contain plastids c. Plant cells differ from animal cells in that plant cells do not contain mitochondria d. Ribosomes are found in eukaryotic cells

c. Plant cells differ from animal cells in that plant cells do not contain mitochondria

Why is it difficult to observe individual chromosomes with a light microscope during interphase? a. The spindle must move them to the metaphase plate before they become visible. b. They leave the nucleus and are dispersed to other parts of the cell. c. They have uncoiled to form long, thin strands. d. Sister chromatids do not pair up until division starts. e. The DNA has not been replicated yet.

c. They have uncoiled to form long, thin strands. Except during the M phase, the DNA is extended, allowing its genes to be transcribed for protein synthesis.

What is one thing NOT true of the endosymbiosis theory: a. Mitochondria are derived from prokaryotes b. Mitochondria were acquired by phagocytosis c. the host cell of endosymbiosis was a prokaryote

c. the host cell of endosymbiosis was a prokaryote

What is the name of the structure that forms during cytokinesis in plant cells?

cell plate made of vesicles from the Golgi apparatus

What name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial cell?

cell wall

G2 checkpoint

cyclin and cyclin-dependent kinases (Cdk) = allosteric regulation (changes shape) Maturation Promoting Factor

Which of the following is found in binary fission but not in mitosis? a. The result produces 2 nuclei. b. Following the process, a membrane separates the 2 copies. c. Replicated strands of DNA separate. d. Duplicated chromosomes attach to the plasma membrane. e. Replication of DNA begins at an origin.

d. Duplicated chromosomes attach to the plasma membrane.

G1 checkpoint

go ahead signal promoted by cyclin and Cdk (cyclin-dependent kinases)

Where is the first check point in cellular division of eukaryotes?

in G1

In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this?

large cells containing many nuclei

Transcribe and translate the following strand of DNA (Find mRNA, tRNA, and the resulting amino acid sequence: 5'-ATG GCT CAG GGT TTC TAG-3'

mRNA: 3'-UAC CGA GUC CCA AAG AUC-5' tRNA: AUG GCU CAG GGU UUC UAG Met Ala Gin Gly Phe End

The cilia and flagella of eukaryotic cells are composed of _____.

microtubules

What organelle carries out cellular respiration?

mitochondrion Mitochondria convert the chemical energy of organic molecules to chemical energy in the form of ATP.

What are the steps in Mitosis?

prophase metaphase anaphase telophase

What is the function of a bacterium's capsule?

protection

In a bacterium, where are proteins synthesized?

ribosomes

Where does protein synthesis take place?

ribosomes

The diameter of a typical eukaryotic cell is approximately ten times the diameter of a typical prokaryote. What is the ratio of the volume of typical eukaryotic:prokaryotic cells?

volume = r^3 = 10^3 = 1000:1