Module 7- Cell Division Flashcards
In Prokaryotes, reproduction occurs through…
Fission
Conjugation
In eukaryotes, reproduction occurs through…
mitosis and meiosis
What is Karyokinesis?
Product of mitosis; Growth, repair, maintenance, asexual reproduction
What are the products of meiosis?
Gametes are formed
Forms sperm and eggs
2N means?
Diploid
N stands for
Haploid
Humans have….
2 sets of 23 chromosomes in humans= 46= 2N
Haploid cells are only found in…
gametes
Name two species discussed in class which do not reproduce sexually.
Dandelions and Bacteria do not sexually reproduce, but they are still considered species. Reproduction does not have to be sexual.
Explain the two ways in Bacteria reproduce
1) binary) fission
Makes a copy and then splits in half
Fission is a fast process
2) Obtain DNA through conjugation (E. Coli)
Only possible in bacteria with a second loop of DNA- called a plasmid
Donor
Pili (Pilus)- or a conjugation tube
Formed by protein extension from the cell wall
Formed between the same strain of bacteria
Plasmid DNA is replicated and transferred through the tube to the recipient cell
Maintains the ability to make more pili
Closest things to bacteria sexual reproduction
Chromatin means…
” Beads on a string”
Chromosomes are
highly condensed
What is a Nucleosome?
unite of a DNA and histone (particular protein); building block
After replication, each chromosome…
consists of 2 double strands ( sister chromatids- each strand of replicated DNA) that are attached to each other at a centromere (portion of DNA not replicated- this holds the DNA together)
At the start of mitosis:
They have to replicate- 2N=92- chromatid
Then in mitosis two daughter cells are formed and they go back to being chromosomes
What are Homologous Chromosomes?
They have the same size, length, gene structure, etc.
What are not considered homologous chromosomes?
xy are not considered to be homologous chromosomes
In a haploid cell…
1 of each type of chromosome is present
In a diploid cell…
2 of each type of chromosome is present; somatic cells
How many chromosomes does an onion have?
16- its gametes have 8
What are the 3 stages of interphase
Growth I
Synthesis
Growth II
What happens in GI?
Organelles replicate (make copies)
What happens in synthesis?
DNA replication- Called chromatids (X)
What happens in GII?
The cell double checks the duplicated chromosomes for errors, manying any needed repairs
Materials for spindle assembled
Cells spend ___ > of their time in interphase
90%
In interphase,
Nucleus is visible- chromosomes look like spaghetti
What are the stages of mitosis?
Prophase
Protometaphase
Metaphase
Anaphase
Telophase
What happens in prophase?
Nucleus disintegrates
Chromosomes become visible because they condense
Looks like roti
What happens in protometaphase?
Chromosomes attach to the spindle ( set of protein fibers called microtubules)
Spindel has opposing poles
Chromosomes separates and move toward opposite poles
Spindle allows for the chromosomes to migrate and separate into two daughter cells
What happens in metaphase?
Chromosomes align in the middle of the cell
What happens in anaphase?
Sister chromatids constricts and the spindle pulls apart the sister chromatids
What happens in telophase?
2 nuclei begin forming
Formation occurs at the metaphase plate- right where the chromosomes align in metaphase
When does cytoplasm divides take place?
In most eukaryotic cells, cytoplasm divides between late anaphase and the end of telophase
What is cytokinesis?
Process of cytoplasmic division
Explain Cytoplasmic Division in animal cells?
contractile ring, also called a cleavage furrow
Actin filaments rings cell midsection, contrats and divides cytoplasm in half
Pinched in half by the formation of microfilaments
Contractile ring is also called a
cleavage furrow
When does Cytokinesis occur?
when chromosomes were in metaphase
Explain cytoplasmic division in plants
Cell plate
Midway between spindle poles via phragmoplast
Divides cytoplasm when it reaches and connects to the parent cell well
Microtubles help lay down the foundation of the cell wall
Daughter cells get smaller and smaller as they divide and this is important in a plant’s regulation
What are several Extrinsic (Environmental factors) of cell regulation?
death of nearby cell
release of growth promoting hormones, such as HGH
SA: V ratio decreases
When cell size decreases, the amount of surface area decreases in ratio to volume
Can stimulate production to increase the surface area
Crowding of cells can inhibit cell
What are several intrinsic factor of cell regulation?
G1
Checkpoint
G2
Checking to make sure the spindle is correct
M (Mitotic phase)
Occurs in anaphase- formation of 2 daughter cells
What is a Positive Regular Molecule?
Cyclins
What are Negative regulator Molecules?
The cell cycle will stop
Can halt cell cycle until specific requirements are met
Retinoblastoma proteins
* tumor-suppressor proteins act primarily at G1 checkpoint
E2F’s (elongation factors) are a group of gene regulating proteins- can promote or inhibit cell cycle
promote cell division if it binds to the chromosomes
If it doesn’t bind- cell division can be halted
What areE2F’s (elongation factors)?
a group of gene regulating proteins- can promote or inhibit cell cycle promote cell division if it binds to the chromosomes
If it doesn’t bind- cell division can be halted
What are the jobs of P53 AND P21 Regulation?
P53 &P21 prevent duplicate of faulty DNA
sTOP s phase from occuring by regulating at the G1 level
P53 promotes transcription of a number of target genes
P21 is one of them
p21 is a negative regulator of cyclin dependent kinases (CDK)
p53 is a tumor suppressor gene
If a mutation were present in a gamete:
Mutated p53 gene
Mutant protein
Hallmark of cancer cell
Cycle keeps going even if DNA is faulty
Markers- looking for proteins suppressing genes
Discuss cancer and cell divison.
Result of unchecked cell division
Breakdown of mechanism that regulate cell cycle
Lead to a protein that does not function as it should
These mistakes will be passed to daughter cells. Eventually, all checkpoints won’t work, rapidly reproducing cells crowd out normal cells, resulting in cancer.
What is a plasmid?
The second loop of DNA of bacteria (E. Coli)
What is a centromere
portion of DNA not replicated- this holds the DNA together)
________ chromosomes contain fragments of DNA exchanged between homologues.
Recombinant
Plants utilize a(n) ________ life strategy.
alternation of generations
A pericentric inversion likely played a role in the evolutionary divergence of ________.
chimpanzees and humans
________ are useful for identifying abnormal chromosomal numbers.
Karyograms
Human ________ are named based on approximate size order.
chromosomes
Mitotic spindle microtubules connect to ________ during prometaphase.
kinetochores
