biology 3rd Flashcards
Mitosis divide cells to produce what?
identical daughter cells
What is Mitosis essential for? (function) List all 2.
1. Growth and development
3. tissue renewal
What are the 3 subphases of interphase?
1. G1- gap phase
2. S- Synthesis
3. G2- 2nd gap phase
What does each of the 3 subphases responsible for?
G1, Synthesis, G2 (2 idea)
1. G1- cellular growth, doubles organelle & membrane mass & cytoplasm
2. synthesis- DNA is DUPLICATED
3. G2- continue growth, prepare for cell division
How many chromosomes are in a human somatic cell? How many are in ONE set?
23- each parents
What does Chromatin consist of? What does it do?
Helps organize the DNA
What is the difference between chromosome, chromatIDS, and chromatIN
chromosome- consist of two into one whole
chromatids- "sisters" two pairs of dna
chromatINS- DNA+ protein that organize DNA
During what phase do sister chromatids separate? What happened?
Centromere splits so each chromatID (two) is now a chromosome (one)
During which phase do chromosome first become visible?
Cytokinesis begins in which phase?
During which phase does the DNA make a copy of itself?
Where are microtubules organized for mitosis?
Single Centrosome replicates during what phase? Mitosis.
interphrase bc doubling everything
What Phase is this? What is happening to the structure of DNA? What is forming? What isn't there?
Mitotic spindle begins to form.
What Phase is this? Structure of DNA? Structure of nuclear envelope? What does it have that prophase doesnt?
- End of interphase; G2
- spaghetti DNA, DNA DUPLICATED
- nuclear envelope isnt broken
What Phase is this? What is happening?
-sister chromatids are separating
What Phase is this? What is happening?
Metaphase (Longest phase)
Chromosomes are lined up on the metaphase plate
What phase is this? What is reforming (2)? What is happening to DNA?
-nuclear envelope & Nucleolus
- decondensed into spaghetti
What phase is this? What is happening to nuclear envelope? DNA structure? microtubules?
- Nuclear envelope= fragmented
- Dna becomes shorter
- microtubules are connected to kinetochore
What phase is this/ what does it divide? What is formed? When does it begin?
- Divides plasma membrane
- cleavage furrow
- late anaphase or early telophase
Cytokinesis depends on cytoskeletal components:
____: separate plasma membrane
____: separate chromosomes
What controls whether or not a cell will divide? (3 factors)
1. intracellular conditions (within cell)
2. extracellular conditions (outside)
What are the three "checkpoints" in cell cycle of mitosis?
What phase are most human cell in? What kind of cells undergo this?
- G0 phase (non-dividing phase) Cell that doesn't receive a "go" signal.
- Damaged liver cells
- Mature muscle and nerve cells
1. Function of PDGF (platelet derived growth factor)? What is its cofactor?
-Cofactors: tyrosine Kinase (phosphate group)
Function: bond with tyrosine kinase to allow cells to pass through the G1 checkpoint
1. What is necessary to pass the G2 checkpoint?
2. What are the two components of ^ & functions?
1. Maturation promoting factor (M-phase-promoting-factor).
I. cyclin dependent kinase- only inactive in absence of cyclin
II. cyclin (recycle)- binds to Cdks to activate them
What is the relationship between cyclin-dependent kinase and cyclin?
direct relationship; increase in one will increase other
How many pairs of autosomes do human cells contain? Why?
all chromosome except 1 pair of a male sex chromosome
Homologous chromosomes have what? What does it tell about the chromosome?
- the location of a gene on a chromosome (strip on chromosome)
Sister chromatids have what? What does it tell about the chromosome?
What phase is it duplicated in?
- identical alleles
tells a specific trait of a gene
What is phases are apart of the interphase? (4)
G0,G1,G2 gaps, S phase (synthesis)
Describe each trait specifically (difference from other)
interphase: 46 chromosomes
prophase: chromosome 2x=92
Prometaphase: Nucleus dissoves. Microtubules attach to centromers.
Metaphase: Chromosomes align in the middle
Anaphase: separate chromosome
Telophase: microtubules disappear. cell division begin.
-Cytokinesis: two daughter cells formed
What does "The Blending Hypothesis" state?
Parents traits form a totally different traits in offspring.
The offspring can never produce the same traits the parents have
What is Particulate Theory? who was it developed by?
traits can be passed on from generations, but not all will appear in each generation.
Why is "Character" different from "trait" ?
Character: inherited feature
Trait: specific character
Give an example of Genotype & Phenotype
Phenotype- purple flowers
Mendel concluded what when he made monohybrids? What did he cross (parents, F1, F2)? What was the result?
- Concluded that the Blending Hypothesis isn't true: trait can not get back to parents. Self cross of purple did not have white, but f2 did.
- crossed true breeding purple & white parents
- F1 produce a purple flower, self cross
- THREE purple: ONE white
What is the difference between genotype and alleles?
Alleles- individual P (dominant), individual p (recessive)
What determines the phenotype(appearance) if alleles at a locus is different?
The dominant allelle
What did Mendel state about the law of independent assortment?
What stage of MEIOSIS is responsible for the this law?
-Law: traits are transmitted to offspring independently. Doesn't matter that y has to go with y.
- Metaphase I
The possible phenotypic combinations ratio seen..
9:3:3:1 (ONLY FOR HETEROZYGOUS)
How is pedigree of a DOMINANT trait different from a RECESSIVE trait? Must be...(Genotype)
- DOMINANT:must have affected parents/homozygous recessive all non-affected
-RECESSIVE:may/may not have affected parents/homozygous recessive all affected
- Homozygous recessive
What is epistatis. Give a class example
The phenotype of one gene influence the phenotype of another
Ex. Have to be in a sequence. Dependent on each other
What did Gregor Mendel proposed? " ____ factor" What does that factor mean?
- passing of traits to offspring from parents/ ancestors
What did Fredrick Griffith propose? How did Oswald Avery contribute to this?
-The Dead S cells (pathogenic) transformed the R cells into pathogenic bacteria
- Discovered that DNA is the transforming agent
What did Hershey & Chase conclude? How (process)?
DNA enters bacterial cell (viral genetic material)
- add sulfur to protein; got supernatant but did not indicate anything
- add phosphorus; supernatant is "active"= viral genetic material
How did Chargaff's rule work?
- Guanine= Cytosine