Lec 2. Mitosis & Meiosis Flashcards
What is the ultimate source of genetic variation?
Mutation
Meiosis provides a mechanism to
recombine variants and increase variability
what is the fundamental unit of heredity?
Genes
Genes come in multiple forms called
alleles
True or false? Genetic info is only carried in DNA
False, it is carried in DNA & RNA
where are genes located?
chromosomes
When do chromosomes separate?
mitosis and meiosis
What is evolution?
Change in genetic frequency in a population over time
Do prokaryotic cells have a nucleus?
No
Do eukaryotic cells have a nucleus?
Yes
What is the cell diameter for prokaryotic cells?
small
What is the cell diameter for eukaryotic cells?
Large
What is the genome for prokaryotic cells?
one circular DNA molecule
What is the genome for eukaryotic cells?
multiple linear DNA molecules
What is the DNA in prokaryotic cells?
no histones in bacteria, some in archaea
What is the DNA in eukaryotic cells
complexed with histones
What is the amount of DNA in prokaryotic cells?
small
What is the amount of DNA in eukaryotic cells?
large
Do prokaryotic cells have membrane-bounded organelles?
No
Do eukaryotic cells have membrane-bounded organelles?
Yes
What are prokaryotes made up of?
eubacteria and archaea
True or False? Viruses are prokaryotic
False. Neither prokaryotic nor eukaryotic
what is one characteristic of Viruses?
Outer protein coat surrounds nucleic acid
True or False? Homologous chromosomes are similar but not identical
True.
How are homologous chromosomes similar but not identical?
Each homolog carries the same genes in same order, but the alleles for each trait may not be the same
What do diploid cells carry?
two sets of genetic info. Two sets of chromosomes
What do haploid cells carry?
one set of genetic info
How many pairs of chromosomes do humans have?
23 pairs
Define centromere
attachment point for spindle microtubules
Define telomeres
tips of linear chromosome
What is the origins of replication?
where the DNA synthesis begins
Define submetacentric
Centromere situated so that one chromosome arm is somewhat shorter
Define metacentric
Centromere in the middle
Define telocentric
Centromere at the end with no short arm
Define acrocentric
Centromere near the end producing a short arm
Define interphase
An extended period between cell divisions, DNA synthesis, and chromosome replication phase
What is M phase?
mitotic phase
what are phase check points?
key transition points
Interphase consists of?
G1,S,G2
What happens during G1?
Growth. Proteins for cell division synthesized
What is G1/S checkpoint?
Regulated decision point
What happens during S in the cell cycle?
DNA synthesis
What happens during G2?
preparation for cell division
What does the G2/M checkpoint do?
Makes sure DNA is completely replicated and undamaged or wont pass
Define mitosis
Separation of sister chromatids
Define cytokinesis
Separation of cytoplasm
Mitosis consists of?
Prophase,prometaphase,metaphase, anaphase, telophase
What happens in prophase?
Mitosis starts. Chromosome condense. Spindle fibers appear.
What happens in prometaphase?
Nuclear membrane dissembles. Spindle fibers attach to chromosome
What happens in metaphase?
Chromosomes align
What happens in anaphase?
Centromeres divide. Chromosomes pulled apart.
What happens in telophase?
Nuclear membrane reforms. Chromosomes decondense. Spindle fibers disappear.
The number of chromsomes per cell equals
the number of functional centromeres
What are three genetic consequences of the cell cycle?
Producing two cells that are genetically identical to each other, newly formed cells contain full complement of chromosomes, each newly formed cell contain approximately half the cytoplasm and organelle content of the original parental cell
What is Meiosis?
production of haploid gametes
What is fertilization?
fusion of haploid gametes
What is the consequence of meiosis?
Genetic variation
What happens during Meiosis I?
separation of homologous chromosome pairs, and reduction of chromosome number by half
What happens during Meiosis II?
Separation of sister chromatids, equational division
What is a chromatid?
one of the two daughter strands of a duplicated chromosome that are joined by a single centromere and separate during cell division to become individual chromosomes.