Flashcards in Exam #4 - Cell Division Deck (108):
Where do cells come from?
Do all cells divide?
What are examples of cells that do NOT divide?
Not all cells divide, but those produced by cell division divide.
What are three reasons why cells divide?
Bacteria only have ___ chromosome and it's _______.
circular - meaning it has to ends
Bacteria have one circular chromosome and it's copied by ____ _________.
Bacterial cells divide by _______ _______.
How many chromosomes do we have?
How are eukaryotic cells more complicated?
1) Membrane bound organelles
2) multiple chromosomes
The ________ and ________ make their own DNA.
mitochondria and chloroplast
What about the E.R and Golgi? What will happen to them during cell division?
They will disassemble and disintegrate into many smaller component parts. The cell divides, and then those parts reassemble and make new E.R and Golgi
What are the two types of cell division in eukaryotes?
Mitosis and meiosis
________ daughter cells.
The daughter cells have _____ the number of chromosomes as the parental cell.
The number of cells in the parental cell will always be a _____ number.
If you have 10 chromosomes, then meiosis gives you daughter cells, each of which have _ chromosomes.
What is the purpose of mitosis? (3)
What is the purpose of meiosis?
Mitosis occurs in body cells, also called _______ cells.
Mitosis is a tightly regulated series of events, unique to eukaryotes. Therefore, this process is controlled by many _______.
______ is the result when cell division goes out of control.
Cell division during the __ phase.
The portion of the cycle in-between cell division is called _________.
Interphase accounts for __% of the cell cycle.
What are the 3 sub phases of interphase?
S phase, G1 and G2
What occurs during S phase?
1) chromosome duplication
2) DNA synthesis
What occurs during G1 and G2?
2) prep for next stage
Gap 1 Is a gap between ____ ______ and ___ ________.
cell division and DNA replication
Gap 2 is between ____ _________ and ____ _________.
DNA replication and cell division
What does the S stand for in the S phase?
Synthesis, DNA Synthesis
G phase means...
In G1, we make the commitment to _______.
Also in G1, we make the raw _______.
In G1, we make the _________ and ________ for DNA synthesis.
nucleotides and enzymes
In G2, we make the raw materials for ____ ________.
The nuclear DNA is carefully INSPECTED in both GAP phases? Why?
The DNA is the code to run the cell...if there's a problem with the code...then continuing this process could be detrimental.
What are the two parts of the M phase?
1) Mitosis - division of the nucleus
2) Cytokinesis - division of the cytoplasm
In adult organisms, only _____ cells divide.
A cell can EXIT THE CYCLE and exist in a non dividing state, which is called ___.
G0 (G zero)
Where ought the cell leave the cycle if it decides to stop dividing?
At the end of G1, after you have grown to a functional size, you stop progressing and leave. You certainly wouldn't go onto S.
How frequently cells 'cycle' depends on the cell ______.
What are three frequencies of mitosis? Provide examples
1) Continuous - skin, GI tract, blood cells
2) Based on need - liver cells
3) Rare/never - neurons (locked in G0)
Most cells are in ____.
Eukaryotic chromosomes can become ____/____ compact.
Nuclear DNA is wrapped around _______.
This complexed material is known as ________.
chromatin - both DNA and protein together
Why do we wrap DNA and protein together?
We need to condense it so it can fit in the nuclease of the cell
One human cell contains _ feet of DNA
DNA + associated proteins =
Over the course of the cell cycle, the DNA becomes ______.
During M phase, the chromatin packs so tightly that the individual chromosomes become ______ _______.
A eukaryotic chromosome: ___ DNA molecule *plus* the associated proteins.
Eukaryotes have ______ DNA molecules
In cell division, the spindle grabs hold of a ________ chromosome, and pulls apart the _________.
When you pull apart the chromatids, how many chromosomes do you have?
A replicated chromosome contains two ______ chromatids.
Each sister chromatid contains:
The DNA's are ________.
They are joined at the _________.
The spindle attaches to the _________.
One chromosome = ___ DNA
90% of the cell cycle is in _________.
If 90% of the cell cycle is interphase, what does a nucleus usually contain?
A _______ is the total genetic information possessed by an organism.
To find that total genetic information, where do you have to look?
Look in any cell
How many different genes are there?
How does a cell distribute the sister chromatids to the daughter cells?
It uses the cytoskeleton
What are the 'steps' of mitosis?
-__________ begin moving to opposite ends
-________ beings to form
What has to happen if the microtubules are going to grab hold of the chromosomes?
***The nucleus has to go away***
Specifically, the **nuclear envelope disintegrates**
This allows microtubules to grab hold of of the chromosomes by the __________.
-nuclear envelope _________.
-microtubules grab chromosomes by their __________.
-chromosomes in the ______
-chromosomes are pulled _______.
-the cell _________.
-____ nuclear envelopes _______.
DECONDENSE so the chromosomes can become chromatin again
What is it that pinches the cell in two?
After telophase, we get cytokinesis, which is...?
the division of the cytoplasm
There are two types of reproduction between eukaryotes, what are they?
1) sexual reproduction - two parents
2) asexual reproduction - only one parent gives rise to offspring
In _______ reproduction, it's mitosis.
Sexual reproduction involves _______.
Meiosis occurs in the _______.
Meiosis produces _______ ( _____ cells).
gametes, germ cells
Meiosis ______ the number of chromosomes.
________ restores the original number.
What advantage can this complexity have?
What's a karyotype?
Seeing all the chromosomes laid out
What are homologous chromosomes?
Chromosome pairs that carry the SAME genes
Where do homologous chromosomes come from?
One from mom, the other from dad
ONE of each pair is inherited from each parent.
SO...each parent gives us ___ copy of a gene.
Each parent gives you one copy of the gene, so you have ___ of each gene.
***It's the _________ chromosomes that are separated by meiosis.***
The genes on homologous chromosomes are often NOT _________.
Any GENE can have multiple VARIATIONS...and we call those variations ________.
What does this mean in chemical terms? What's so different about the different alleles if they're the same gene?
**They have slight differences in their nucleotide sequence**
DO NOT confuse homologous chromosomes with sister chromatids !!!!!!
Which term refers to identical DNA's?
Which ones are present throughout the mitotic cell cycle?
Sister chromatids - IDENTICAL
Where do the homologous chromosomes come from?
Mom and dad! Present throughout the cell cycle
How many sex chromosomes do we have?
That means we have 44 ________.
autosomes - all the non-sex chromosomes
Males have an _ and an _ chromosome.
X and an X
Females have an _ and a _ chromosome.
X and a Y,
X and Y are not _________, which means they must have different ______.
Somatic cells have ___ sets of chromosomes.
-i.e: the homologous pairs!
-one maternal, one paternal
-Somatic cells are _n, or _______.
Gamets have ___ set.
-they are _, or ________.
Meiosis separates ....?
In humans: **n= one set from one parent**
n = __ chromosomes
2n = __ chromosomes
n = 23 (22 autosomes + 1 sex chromosome)
2n = 46 (44 autosomes + 2 sex chromosomes
A zygote has __ chromosomes.
Meiosis has ___ consecutive rounds of cell division (I and II)
Meiosis reduces chromosome # by _____.
Steps of meiosis...
Every single cell division is preceded by ___ ________.
Meiosis I occurs, which separates...?
Meiosis II occurs, which separates...?
the homologous chromosomes
the sister chromatids
Meiosis _ Is what makes meiosis unique. It's nothing like mitosis.
Meiosis _ IS mitosis.
Meiosis II IS mitosis.
**You're separating separating sister chromatids**
**Which one takes you from diploid to haploid?**
Meiosis I !!!!!!!!!! Diploid to haploid, BOOM