Mitosis Flashcards
Cell division
Process by which a parent cell divides into two or more daughter cells
Unicellular division
Produces an entire organism
Multicellular division
Develop from a fertilized egg, a zygote
Cell cycle
The life of a cell from when it is first formed to when it divides into two cells
Roles of cell division
Growth, getting bigger; repair, healing wounds; reproduction, sexual or asexual
Genome
The cell’s DNA, genetic information
Chromosomes
A single DNA molecule, located in nucleus
Chromosomes in a human somatic cell
46, because there two sets of 23, one from each parent
Somatic cells
All cells but sex cells, aka, diploids
Gamete
Reproductive cells, aka, haploid
Chromosomes in a human gamete cell
23
Chromatin
what chromosomes are made of, loosely packed DNA used for transcription
DNA molecules in a human somatic cell
46
Centromere
Specialized region when 2 chromatids attach
Chromatid
1 DNA molecule stuck to another, one copy of a newly copied chromosome
Replicated chromosome
An X made of two sister chromatids connected n at the centromere
Sister chromatid cohesion
When chromatids are attached along their length by adhesive proteins called cohesins
What is Mitosis?
The division of the nucleus
Cytokinesis
Division of the cytoplasm
What is Meiosis?
Production of gametes, sex cells. Reduces the number of daughter cells
What happens to the DNA
Each chromosome has a single DNA molecule. Once replicated, there are sister chromatids-each has a copy of the DNA. Mechanical processes separate them into two identical daughter cells
Interphase
Made of 3 phases and takes 90% of the time of cell cycle; the cells grows, copies it’s chromosomes and prepares for cell division: G1, S, G2. DNA is in chromatin form.
G1 phase
Cell grows
S phase
Copies it’s chromosomes; DNA synthesis
G2 phase
Grows and completes preparations for cell division; protein synthesis
DNA
Two antiparallel strands, running opposite each other. There is a 5’ end and a 3’ end made of nucleotides. Bonds are A and T, G and C. When replicating A and U.
DNA replication
Parent DNA strand broken by helicase, DNA polymerase brings the correct nucleotide to the parent strand to start building the daughter strand. Builds the 5’ end first.
Helicase
Enzyme that breaks hydrogen bonds exposing the nitrogen base of each strand
Semi-conservatory strands
New DNA uses 1 strand of the previous parent cell and 1 from the new daughter cell
DNA polymerase
Brings nucleotides to build new strands of the exposed old strand
Mitotic spindle
Forms in cytoplasm during prophase, made of proteins and microtubules, arises from centrosome
Centrosome
Microtubule organizing center, replicates during interphase, moves apart and grows centrioles
Kinetochore
A structure of proteins associated with specific sections of chromosomal DNA at the centromere
G0 (Gee-not)
During G1 when cells decide they don’t need to divide
Mitosis
The division of the nucleus of the cell, has 5 stages: prophase, prometaphase, metaphase, anaphase, telophase
Prophase
Chromatin fibers tightly coiled, nucleoli disappear, sister chromatid cohesion, mitotic spindle begins to form, centrosomes move away from eachother
Prometaphase
Nuclear envelope fragments, microtubules extend, chromosomes condensed, mitotic spindle and some attach to kinetochore
Metaphase
Centrosomes at poles, chromosomes on metaphase plate - a pane between the poles
Anaphase
Cohesion proteins cleaved, chromosomes move to opposite ends, cell elongates
Telophase
Daughter nuclei form in cell, nuclear envelopes and nucleoli appear, mitosis is complete
Cytokinesis
Division of cytoplasm to form two cells, animal cells pinch in two forming a cleavage furrow, plant cells grow a cell plate in the middle of the cell which forms into a cell wall.
Nonkinetochore
Spindle fibers that connect to themselves
kinetochore microtubules shorten at which end during anaphase?
At the kinetochore end by depolymerization
Cytokinesis animal cell
Cleavage furrow forms, actin and myosin cause the ring to contract until cell is pinched in two
Cytokinesis plant cell
Vesicles from golgi and cell wall material coalesce in cell center to form a cell plate, it enlarges until it fuses to the membrane, becomes the cell wall when cell splits
Protein synthesis
Occurs in the ribosome. Uses, transcription and translation
Types of RNA
Messenger RNA, Ribosomal RNA, Transfer RNA
Messenger RNA
Built within the message from DNA and takes info the the ribosome
Ribosomal RNA
Makes up the structure of the ribosome
Transfer RNA
Carries amino acids from cytoplasm to ribosome
Transcription
In the nucleus, DNA splits to expose nitrogenous bases. mRNA strand builds with complimentary bases on the antisense strand
Translation
mRNA strand travels out of pore to the ribosome, each group of three nitrogen bases (codon) matches to a tRNA (anitcodon) which carries an amino acid, which then has a condensation reaction between others
Binary Fusion
DNA of the bacterial chromosome begins to replicate at the origin of replication, forming two origins, one moves to the other end of the cell, which elongates. Plasma membrane grows outward, dividing the cell
Cell cycle control system
Molecules in the cytoplasm trigger and coordinate key events
Checkpoint
A control point where signals regulate the cell
Cyclins
A group of proteins used to ensure the timing of the tasks and progression of the stages in the cell cycle
Protein kinase
Enzyme that activates proteins by phosphorylating them
How cyclins and kinase work together
Cyclin binds to kinase to activate it, then fades away, then kinase grabs a phosphate from ATP and attaches it to a different protein, now those proteins have energy to do their job and continue their role in the cell cycle
Growth factors
A protein releases by certain cells that stimulate other cells to divide
Density dependent inhibition
Crowded cells stop dividing
Anchorage dependence
To divide, animals cells must be attached to a substance
MPF
Maturation-promoting factor: triggers cells passage into M phase
Transformation
Process converting a normal cell to a cancer cell
Metastasis
Spread of cancer to locations different than the origins
Benign tumor
Remains at normal site
Malignant tumor
Impairs the functions of more than one organ
