Meiosis and Mitosis
Card Set Information
Meiosis and Mitosis
Biology Meiosis Mitosis
meiosis and mitosis
What is mutation?
A heritable change in genetic material
Where does mutation occur?
In the DNA
What is a Point Mutation?
A mutation that affect only a single base
What is base substitution?
a mutation that substitutes a single base for another
What are frameshift mutations?
Addition or deletion of a number of bases that are not in multiples of three
What is a translocation mutation?
Two chromosomes break and switch ends, creating chimeric genes
What two mutations affect amino acid sequences?
Silent and Missense mutations
What is a silent mutation?
Does not alter the amino acid sequence
What is a missense mutation?
Changes a single amino acid in a polypeptide
What is a nonsense mutation?
changes from a normal codon to a stop codon
Where does mutation occur in Germ line cells?
In the sperm and egg cell or the gamete
Where does mutation occur in somatic cells?
All other cells
What are the two components of DNA repair?
Detection or repair
define direct repair?
A repair enzyme recognizes an incorrect structure in the DNA and directly converts it
Define Nucleotide Excision Repair (NER)
Portion of DNA strand containing an abnormal nucleotide is removed and replaced
Define Methyl-directed Mismatch Repair
A base pair mismatch is detected, and a strand of surrounding DNA is removed and replaced
What are Carcinogens?
agents that increase the likelihood of developing cancer
What are Activators?
activator proteins stimulate RNA polymerase to initiate transcription
What are Repressors?
repressor proteins inhibit RNA polymerase from initiating transcription
What is the TATA box?
5’ – TATAAAA –3’
What is the Transcriptional Start Site
Where Transcription starts
What are the two Regulatory or Response Elements
Enhancers or silencers
Whats is Histone acetyltransferase
attaches acetyl groups to histone proteins so they don’t bind DNA as tightly
What are Karyotypes?
Reveals number, size, and form of chromosomes in an actively dividing cell (22 Pairs)
What are the three phases of Interphase?
G1, S and G2
What happens in the G1 phase of Interphase?
First gap; cell grows and organelles duplicate
What happens in the S phase of Interphase?
Synthesis of DNA
What happens in the G2 phase of Interphase?
Second gap; cell makes proteins necessary for mitosis
What is Interphase?
Phase of the cell cycle during which the chromosomes are decondensed and found in the nucleus
What are the four phases of mitosis?
PMAT- Prophase, Metaphase, Anaphase, Telophase.
What happens during Prophase?
Chromatids condense into highly
compacted structures - Pull together
What happens during Metaphase?
Organized into a single row – put into place by microtubules. Middle of the Cell
What happens during Anaphase?
Connections are broken between sister chromatids. Apart
What happens during Telophase?
Nuclear membranes now reform to produce two separate nuclei
What happens in Prophase 1?
Chromosomes condense, bivalents form and nuclear membrane break down.
What happens in Metaphase 1?
the bivalent pairs are organized along the metaphase plate as a double row
What happens during Anaphase 1?
Connections break, chromatids migrate to one pole
What happens during Telophase 1?
Chromatids decondense; nuclear membrane re-form
What is a Euploid?
Normal number of chromosomes
What is a Polyploid?
3 or more sets of chromosomes
What is an Aneuploidy?
Abnormal number of a particular chromosome