Cellular Reproduction Flashcards

1
Q

Describe the process of binary fission in prokaryotes

A

-circular DNA is replicated
-reproduction is clonal
-new chromosomes partitioned to opposite parts of the cell
-origin of replication and proceeds in two directions to site of termination
-septum forms to divide the cell into two cells

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2
Q

Describe how the cell cycle is controlled by both positive and negative mechanisms.

A

Positive:
Cyclins interact with Cdks and function to push through the checkpoints and allow cell cycle to succeed. (Were they inhibited, cell would not progress through cell cycle.)

Negative:
Protein p53 (tumor suppressor gene) halts cell cycle, can program cell death. Rb

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3
Q

Distinguish between chromosome forms, homologous pairs and sister and non-sister chromatids

A

Sister chromatids:
-Dyad chromosomes consist of 2 sister chromatids.
-The kinetochore is a protein complex that attaches to the centromeres of the sister chromatids.
-They stay attached through the protein cohesin.

Non-sister chromatids:
-Two chromatids from two different homologous chromosomes

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4
Q

Describe the structure of prokaryotic and eukaryotic genomes

A

Genome: A cell’s genetic information encoded in DNA as one or more double-stranded molecules.

A genome can consist of a single DNA molecule (common in prokaryotic cells) or multiple DNA molecules (common in eukaryotic cells)

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5
Q

Describe the structures that underlie the various levels of chromosome compaction

A

-Each chromosome consists of DNA tightly coiled by proteins called histones.

-This DNA histone complex is called a nucleosome and is connected by linker DNA.

-Nucleosomes are coiled into a chromatin fiber that is uncondensed during interphase.

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6
Q

Describe the eukaryotic cell cycle

A

Interphase (G1, S, G2)

M (mitosis)

C (cytokinesis)

When it exits the cell cycle, it is considered to be in G0.

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7
Q

Describe the three phases and key events of interphase

A

G1 (gap phase 1):
-primary growth phase
-longest phase

S (synthesis):
-replication of DNA
-centrosome is duplicated

G2 (gap phase 2):
-organelles replicate
-microtubules organize

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8
Q

Explain how the cytoplasmic content is divided during cytokinesis

A

Cytoplasmic contents divide by using the cleavage furrow with the pinching method,
pinches inward along the cell’s equator until two daughter cells form. In plant cells, a cell
plate forms along the equator of the parent cell, then a new plasma membrane and cell
wall form along each side of the cell plate.

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9
Q

Distinguish the role of checkpoints in the control of the cell cycle

A

G1/S checkpoint:
-cell “decides” to divide
-primarily influenced by internal and external signals

G2/M checkpoint:
-cell makes a commitment to mitosis
-assesses success of DNA replication

Late metaphase (spindle) checkpoint:
-cell ensures that all chromosomes are attached to the spindle

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10
Q

Explain how the three internal control checkpoints occur at the end of G1, at the G2/M
transition, and during metaphase

A

G1/S checkpoint:
-cell “decides” to divide
-primarily influenced by internal and external signals

G2/M checkpoint:
-cell makes a commitment to mitosis
-assesses success of DNA replication

Late metaphase (spindle) checkpoint:
-cell ensures that all chromosomes are attached to the spindle

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11
Q

Prophase

A

-chromosomes condense and become visible
-centrioles move to opposite poles to form spindle fibers
-nuclear envelope breaks down
-nucleolus disappears

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12
Q

Prometaphase

A

-chromosomes continue to condense
-kinetochores appear at the centromeres
-mitotic spindle microtubules attach to kinetochores

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13
Q

Metaphase

A

-mitotic spindle is fully developed
-chromosomes are lined up at the metaphase plate
-each sister chromatid is attached to a spindle fiber originating from opposite poles

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14
Q

Anaphase

A

-key event is cohesin proteins binding the sister chromatids together break down
-sister chromatids are pulled towards opposite poles
-non-kinetochore spindle fibers lengthen, elongating the cell

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15
Q

Telophase

A

-spindle apparatus disassembles
-nuclear envelope forms around each set of monad chromosomes
-chromosomes begin to uncoil
-nucleolus reappears in each nucleus
-golgi and ER reform

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16
Q

Multicellular organisms depend on cell division for

A

-Growth
-Repair
-Development from fertilized cell

17
Q

Crossing Over

A

Exchange of genetic material between non-sister chromatids