DNA & Cell Cycle Flashcards
interphase
the longest part of a cell’s life - the cell grows and makes a copy of its DNA (G1+S+G2)
G1 & G2
cell growth & copies organelles
S1
synthesis of DNA
mitosis
the nucleus divides
prophase
DNA condenses into chromosomes, nuclear membrane disappears
metaphase
chromosomes line up in the center
anaphase
chromosomes are separated to opposite poles of the cell
telophase
two new nuclei are created
cytokinesis
the cell completely divides into two daughter cells, the cytoplasm divides
cancer
disruptions in the cell cycle are when the cell loses control of cell division & cannot stop dividing – results in abnormal cell growth called tumors = cancer
mitosis
creates body cells (2 daughter cells)
meiosis
creates sex gametes (sperm & egg) [single cell divides twice, produces 4 cells with half of the genetic info]
how many divisions does mitosis have?
1
how many divisions does meiosis have?
2
how many daughter cells does mitosis result in & are they identical or unique?
2 identical daughter cells
how many daughter cells does meiosis result in & are they identical or unique?
4 unique daughter cells
what type of reproduction does mitosis go thru?
asexual
what type of reproduction does meiosis go thru?
sexual
things that occur that cause genetic variation
crossing over, segregation of alleles, independent assortment
segregation of alleles
alleles separate & move into a different haploid gamete sex cell
independent assortment
traits don’t follow each other, they move independently
DNA structure
double helix, anti-parallel strands, backbone = sugar & phosphate, steps = paired bases
cell cycle has
regulated cell growth, replication & division
G0
the resting phase where cells convert glucose to ATP, make proteins & other general processes
mutations
mistakes in chromosomes & changes in DNA cause mutations
checkpoint
where the DNA is checked & the cell cycle can be stopped
how many chromosomes do body cells have
46
how many chromosomes do sex cells have
23
does mitosis or meiosis cause genetic variation
meiosis
purpose of mitosis
growth & repair
purpose of meiosis
sexual reproduction
point mutation
where one nucleotide is changed so only one amino acid may be affected
substitution
one nucleotide takes the place of another in the sequence & can either result in a change or no change
frameshift mutation
Where a nucleotide is deleted or inserted into the DNA, shifting everything up or down. Shifts or changes the way a DNA sequence is read and transcribed. Changes the amino acid sequence starting from the mutation point. Protein is usually non-functional (doesn’t work)
insertion
when a base is added
deletion
when a base is removed
what causes chromosomal mutations
problems that occur during meiosis, mutagens (chemicals, radiation, UV, etc)
what are the results of chromosomal mutations
change in # of chromosomes in a cell, change in the structure of the chromosome, affects entire chromosome & protein production
translocation
when a portion of one chromosome is transported to another chromosome
nondisjunction
the failure of homologous chromosomes to separate properly during cell division. It produces individuals with either extra or missing chromosomes
