Section 5: Cell Division Flashcards by michael perna

What is the term for nuclear division?

What follows nuclear division?

Karyokinesis

Cytokinesis

How well did you know this?

Not at all

Perfectly

In diploid cells, there are 2 copies of every______, forming a pair, which is called a ______

Chromosome

homologous chromosome

How well did you know this?

Not at all

Perfectly

Humans have ____ chromosomes, ____ homologous pairs, and a total of _____ chromatids

46 chromosomes

23 pairs

92 chromatids (depending upon stage of division 1)

How well did you know this?

Not at all

Perfectly

These are also known as centrosomes. A pair of them lay outside the nucleus

Microtubule organizing centers

How well did you know this?

Not at all

Perfectly

In animal cells, each MTOC contains a pair of

Centrioles

How well did you know this?

Not at all

Perfectly

In this phase of MITOSIS, the nucleus dissassembles

Prophase

How well did you know this?

Not at all

Perfectly

During prophase of mitosis, the nucleus disassembles and and the ______ appear

What condenses into chromosomes?

What breaks down?

What two things are formed?

Nucleolus

Chromatin

The nuclear envelope

Mitotic Spindle and microtubules

How well did you know this?

Not at all

Perfectly

What are the microtubules of the mitotic spindle that is formed during prophase of mitosis made of?

Where do they begin to connect with?

Tubulin

Kinetochores

How well did you know this?

Not at all

Perfectly

The protein structure on chromatids where the spindle fibers attach during cell division to pull sister chromatids apart.

Kinetochore

How well did you know this?

Not at all

Perfectly

During this phase of mitosis, chromosomes line up single file at center

Metaphase

How well did you know this?

Not at all

Perfectly

During the metaphase of mitosis, each chromatid is complete with a ______ and a _____

Once separated, it is a

To keep track of total, count the number of….

Centromere and kinetochore

Chromosome

Centromeres

How well did you know this?

Not at all

Perfectly

During mitosis, once the chromatid is separated, that is the end of _______

The chromosome number does what during the next phase?

metaphase

Doubles

How well did you know this?

Not at all

Perfectly

Karyotyping occurs during which phase of mitosis?

Metaphase

How well did you know this?

Not at all

Perfectly

During this phase of mitosis, microtubules shorten, and each chromosome is pulled apart into two ________

Anaphase

Chromatids

How well did you know this?

Not at all

Perfectly

Remember that when two DNA molecules are joined together, each molecule is called a chromatid and the two of the molecules are called a duplicated chromosome. When a DNA molecule(and proteins) is not attached to another one then that single molecule of DNA is not a chromatid but an unduplicated chromosome.

!! Important distinction

How well did you know this?

Not at all

Perfectly

During anaphase of mitosis, what happens to the chromosome number?

It doubles, because duplicated chromosomes are pulled apart to opposite poles

How well did you know this?

Not at all

Perfectly

What is it called when the chromosomes are pulled to apart to opposite poles of the cell during mitosis?

Disjunction

How well did you know this?

Not at all

Perfectly

During mitosis, at the end of _______, each pole has a complete set of chromosomes, same as original cell before replication

Anaphase

How well did you know this?

Not at all

Perfectly

During mitosis, this is the phase of nuclear division

What develops?

The chromosomes uncoil and become…

What reappear?

Telophase

Nuclear envelope

Chromatin

Nucleoli

How well did you know this?

Not at all

Perfectly

This is a particular region of the nucleus containing chromosomal regions of cells

Nucleolus

How well did you know this?

Not at all

Perfectly

What begins during the later stages of mitosis, aka at the end of anaphase?

Cytokinesis, the division of cytoplasm to form 2 cells

How well did you know this?

Not at all

Perfectly

During cytokinesis, these microfilaments shorten, pulling the plasma membrane to the center (animals)

What is this process called?

Actin and myosin

Cleavage furrow

How well did you know this?

Not at all

Perfectly

During cytokinesis in plants, vesicles from Golgi bodies migrate and fuse to form…

Out growth occurs and merging with the _____ separating the two new cells.

Do cells actually separate?

What cements adjacent cells together, then?

Cell plate

Plasma membrane

No, they are cemented together

Middle Lamella

How well did you know this?

Not at all

Perfectly

This phase begins after mitosis and cytokinesis are complete, and consists of G1, S, and G2 phases

Interphase

How well did you know this?

Not at all

Perfectly

What are the phases of the cell cycle in order?

M, G1, S, G2,

During the ___ phase of interphase, the second molecule of DNA is replicated from the first, forming sister chromatids

S phase

Is more time spent during interphase or mitosis?

Interphase

During interphase, does growth only occur during G's?

No, it occurs in all 3 interphases

During which interphase are the materials for the next mitotic division prepared?

There are checkpoints at each interphase to make sure things are going as planned Near the end of ____, cell growth is assessed and favorable conditions are checked. If this fails, the cell enters Near the end of ____, checks for sufficient mitosis promoting factor levels required to proceed There is an M checkpoint during mitosis that triggers start of...

G1 G0 G2 G1

This part of MEIOSIS is reduction division

Meiosis 1

In this PHASE of meiosis, homologous chromosomes pair at the plate and migrate to opposite poles Is there separation of sister chromatids? What develops? Microtubules attach to ____ Crossing over means genetic ____ This could change the ___ sequence

Prophase I No. Spindle Kinetochores recombination Nucleotide sequnce

This is the term for when homologous chromosomes pair up during prophase I of meiosis The pairs are referred to as ___ or ____

Synapsis Tetrads or bivalents

During prophase I of meiosis, this is the region where crossing over occurs of non-sister chromatids

Chiasmata

During prophase I of meiosis, this is the protein structure that temporarily forms between homologous chromosomes: gives rise tothe tetrad w/ chiasmata and crossing over

Synaptonemal complex

How many phases does prophase I of meiosis have? What are they?

5 ``` Leptotene Zygotene Pachytene Diplotene Diakinesis ```

In this step of prophase I, chromosomes start condensing

Leptotene

In this step of prophase I, synapsis beings; the synaptonemal complex is forming

Zygotene

In this step of prophase I, synapsis is complete, and crossing over occurs

Pachytene

In this step of prophase I, the synaptonemal complex disappears and the chiasma is still present

Diplotene

In this step of prophase I, the nuclear envelope fragments, and chromosomes complete condensing, tetrads are ready for metaphase

Diakinesis

During this phase of MEIOSIS, homologous pairs are spread across the metaphase plate _____ are attached to kinetochores of one member of each homologous pair. They one member then attach to the 2nd member of the pair

Metaphase I Microtubules

During this phase of meosis, homologues within tetrads uncouple and are pulled to opposite sides The term for pulling apart is...

Anaphase I disjunction

During this phase of meiosis, the nuclear membrane develops. Each pole forms a new nucleus What proportion of chromosomes do the new nucleus' have from the beginning?

Telophase I Half the chromosomes

This is the chromosome reduction phase of meiosis to haploid

Telophase I

Depending upon the species, what may occur after telophase I of meiosis?

Interphase

In this part of meiosis, chromosomes spread across metaphase plate and sister chromatids separate and migrate to opposite poles. It is similar to mitosis.

Meiosis II

In this phase of meiosis, the nuclear envelope disappears and the spindle develops, etc, Is there chiasmata or crossing over?

Prophase II No.

During this phase of meiosis, the chromosomes align on a plate like in mitosis but now with half the number of chromosomes (no extra copy)

Metaphase II

During this phase of meiosis, each chromosome is pulled into 2 separate chromatids and migrate to opposite poles of the cell

Anaphase II

During this phase of meiosis, the nuclear envelope reappears and cytokinesis occurs How many cells are created? Are they diploid or haploid?

Telophase II 4 haploid (each chromosome=1 chromatid)

What type of cell division occurs in somatic cells? What type of cell division occurs in gametes?

Mitosis Meiosis (egg, sperm, pollen)

This is the fusion of two haploid gametes It forms a... This is meoisis, right?

Fertilization/syngamy diploid zygote

In plants what produces spores? Are these diploid or haploid? Spores undergo MEIOSIS/MITOSIS to become multicellular Once multicellular, they are called

Sporangia Haploid Mitosis Gametophytes

Gametophytes are diploid or haploid? The gametes fuse and produce a This grows to become a

Haploid, since spores are already haploid Diploid Zygote (2n) Sporophyte

Cells in the sporophyte (sporangia) undergoes MITOSIS/MEIOSIS to produce haploid spores which germinate and repeat the life cycle

Meiosis (check out diagram in feralis notes)

This is a term primarily used to describe the life cycle of plants (taken here to mean the Archaeplastida). A multicellular gametophyte, which is haploid with n chromosomes, alternates with a multicellular sporophyte, which is diploid with 2n chromosomes, made up of n pairs. A mature sporophyte produces spores by meiosis, a process which reduces the number of chromosomes to half, from 2n to n.

Alternation of generations (alternation of diploid and haploid stages in plants)

Genetic variation (genetic recombination during meiosis and sexual reproduction) results from 3 events. What are they?

Crossing over during Prophase I Independent assortment of homologues during metaphase (which chromosome goes into which cell) Random joining of gamete aka germ cells (which sperm fertilizes which egg)

In the regulation of the cell cycle, the volume gets much larger when cells grow. When this value is small, exchange is hard, leading to cell death or cell division to increase surface area. When the value is large, exchange becomes much easier What is the volume equation? What is the SA equation?

Surface to volume ratio 4/3πr^3 4πr^2

In the regulation of the cell cycle, the genome size remains constant throughout life. As the cell grows, the volume increases. The value will be small and thus exceed the ability of its genome to produce sufficient amounts of regulator of activites

Genome to volume ratio

What do some large cells have to deal with small genome to volume (G/V) ratios?

They are multinucleated (paramecium, human skeletal muscle)

In the checkpoints of the cell cycle, this is the restriction point, the most important one. At the end of the phase, if the cell is not ready to divide it may arrest here and never proceed or wait until it is ready What phase will it go to if it is not ready? what cells rarely proceed to division after maturing, and therefore go to G0?

G1 checkpoint G0 phase Nerve and muscle cells

In the checkpoint of the cell cycle, this one evaluates the accuracy of DNA replication and signals whether to begin mitosis

G2 checkpoint

In the checkpoints of the cell cycle, this occurs during metaphase and ensure microtubules are properly atteached to kinetochores

M checkpoint

These are enzymes that activate proteins that regulate cell cycle by phosphorylation What are they activated by?

Cyclin-dependent kinases (CDKs) Cyclin (duh)

The plasma membrane has receptors for _______ that stimulate cell for division (such as damaged cell)

growth factors

This occurs when cells stop dividing when surrounding cells density reaches maximum.

Density Dependent Inhibition

Most cells only divide when attached to an external surface such as neighboring cells or side of culture dish. This regulation is called

Anchorage dependence

What type of cells defy all 5 of the cell specific conditions mentioned before (Checkpoint, CDKs, Growth factors, Density dependent inhibition, anchorage dependence)

Cancer cells

How many chromosomes are there in the anaphase of mitosis if a cell has 46 chromosomes at the beginning? What can be counted to give this value?

92 (46 chromosomes made of 2 sister chromatids are pulled apart to give 92 chromosomes) Centromere

At anaphase I, how many chromosomes are there if a cell has 46 chromosomes at the beginning?

46 (23 chromosomes that are pulled to each pole, no separation of sister chromatids at anaphase I)

Do plants have centrioles? Why or why not?

No The cell plate forms

Which has no genetic variation, mitosis or meiosis?

mitosis