Test #3 Vocabulary Flashcards
Transition
Base substitution in which a purine replaces a purine or a pyrimidine replaces a pyrimidine
Transversion
Base substitution in which a purine replaces a pyrimidine or a pyrimidine replaces a purine
Insertion
Addition of one or more nucleotides
Deletion
Deletion of one or more nucleotides
Frame-shift mutation
Insertion or deletion that alters the reading frame of a gene
In-frame deletion or insertion
Deletion or Insertion of a multiple of three nucleotides that does not alter the reading frame
Expanding nucleotide repeats
Increases the number of copies of a set of nucleotides
Forward mutation
Changes the wild-type phenotype to a mutant phenotype
Reverse mutation
Changes a mutant phenotype back to the wild-type phenotype
Missense mutation
Changes a sense codon into a different sense codon , resulting in the incorporation of a different amino acid in the protein
Nonsense mutation
Changes a sense codon into nonsense (stop) codon, causing premature termination of translation
Silent mutation
Changes a sense codon into a synonymous codon, leaving the amino acid sequence of the protein unchanged
Neutral mutation
Changes the amino acid sequence of a protein without altering its ability to function
Loss-of-function
Causes a complete or partial loss of function
Gain-of-function
Causes the appearance of a new trait or function or causes the appearance of a trait in inappropriate tissue or at an inappropriate time
Lethal Mutation
Causes premature death
Supressor mutation
Suppresses the effect of an earlier mutation at a different time
Intragenic suppressor mutation
Suppresses the effect of an earlier mutation within the same gene
Intergenic suppressor mutation
Suppresses the effect of an earlier mutation in another gene
Go phase
Stable non dividing period of variable length
G1 phase
growth and development of the cell; G1/S checkpoint
S Phase
Synthesis of DNA
G2 phase
biochemical preparation for cell division; G2/M checkpoint
Prophase
Chromosomes condense and mitotic spindle forms
Prometaphase
Nuclear envelope disintegrates, and spindle microtubules anchor to kinetochores
Metaphase
Chromosomes align on the metaphase plate; spindle-assembly checkpoint
Anaphase
Sister chromatids separate, becoming individual chromosomes that migrate toward spindle poles
Telophase
Chromosomes arrive at the spindle poles, the nuclear envelope re-forms, and the condensed chromosomes relax
Cytokinesis
Cytoplasm divides; cell wall forms in plant cells.
What are the stages of interphase?
G1, S, and G2 phase
What are the stages of M phase
prophase, pro metaphase, metaphase, anaphase, telophase, cytokinesis
Prokaryotic vs. Eukaryotic
Prok
- single celled
- circular DNA
Eukaryotic
- multicellular
- linear DNA
- membrane bound organelle
Characteristics of viruses?
- outer protein coat surrounding nucleic acid
- not alive
- neither prokaryotic or eukaryotic
Diploid organism
two sets of chromosomes organized as homologous pairs
homologous
chromosomes have the same genes + sequences
Diploid cells have
two sets of chromosomes
What is interphase?
an extended period between cell division, DNA synthesis, and chromosome replication phase
G1/S Checkpoint
regulated decision point
G2/M checkpoint
only passed if DNA is completely replicated and undamaged
Mitosis (M phase)
separation of sister chromatids
Cytokinesis
separation of cytoplasm
Meiosis
the production of haploid gametes
fertilization
the fusion of haploid gametes (egg & sperm)
Genetic Variation
consequences of meiosis
Meiosis Interphase I
DNA synthesis and chromosome replication phase
Meiosis I
separation of homologous chromosome pairs, and reduction of the chromosome number by half
Meiosis II
separation of sister chromatids, also known as equational division
synapsis
close pairing of homologous chromosome
tetrad
closely associated four sister chromatids of two homologous chromosomes
Crossing over
exchange of genetic information between sister chromatids
What are the mechanisms for genetic variation in meiosis?
crossing over and anaphase I
Metaphase I
random alignment of homologous pairs of chromosomes along the metaphase plate
Anaphase I
separation of homologous chromosome pairs, and the random distribution of chromosomes into two newly divided cells
Telophase I/ Interkinesis
the period between meiosis I and meiosis II
Prophase I
chromosomes condense, homologous chromosomes synapse, crossing over takes place, the nuclear envelope breakdown , and the mitotic spindle forms.
Metaphase I
Homologous pairs of chromosomes line up on the metaphase plate
Anaphase I
the two chromosomes (each with two chromatids) of a homologous pair separate and move toward opposite poles
Telophase I
chromosomes arrive at the spindle poles
Cytokinesis I
The cytoplasm divides to produce two cells, each having half the original number of chromosomes
Interkinesis
In some types of cells, the spindle breads down, chromosomes relax, and a nuclear envelop re-forms, but no DNA synthesis takes place.
Prophase II
chromosomes condense, the spindle forms and the nuclear envelope disintegrates
metaphase II
individual chromosomes line up on the metaphase plate
Anaphase II
sister chromatids separate and move as individual chromosomes toward the spindle pores
Telophase II
chromosomes arrive at the spindle poles; the spindle breaks down and a nuclear envelope re-forms
Cytokinesis
the cytoplasm divides
What are the steps of meiosis I?
prophase I, metaphase I, anaphase I, telophase I, cytokinesis, interkinesis
What are the steps of meiosis II?
prophase II, metaphase II, anaphase II, telophase II, cytokinesis
What takes place in meiosis II but not in meiosis I?
separation of chromatids
What hold sister chromatids together?
cohesins
What holds sister chromatids together in meiosis I?
Shugoshin
germline mutation
passed on to offspring through sexual reproduction
somatic mutation
passed through mitosis
What is a suppressor mutation?
a mutation that hides or suppresses the effect of another mutation
Where does intragenic suppressor mutation occur?
in genes containing the mutation being suppressed
How is a suppressor mutation different from a reverse mutation?
A reverse mutation restores the original phenotype by changing the DNA sequence back to the wild-type sequence. A suppressor mutation restores the phenotype by causing an additional change in the DNA at a site that is different from that of the original mutation
What are the four categories that cause mutations?
spontaneous replication errors, spontaneous chemical changes, chemically induced mutations , radiation
What are the types of spontaneous replication errors?
tautomeric shifts, mispairing, incorporation error by DNA pol, deletions and insertions, strand slippage, unequal cross over
What is a tautomeric shift?
wrong isomer of guanine
What does indels mean?
insertions and deletions
What are the types of spontaneous chemical changes due to polar water molecules?
Depurination and deamination
What is depurination?
loss of purine (losing an entire base)
What is deamination?
loss of an amino group (creates bp changes)
What are chemically induced mutations?
mutagen and base analogs
What is a mutagen?
environmental agency that increases rate of mutation
What are base analogs?
chemicals with structure similar to NTP
What is AZT?
nucleotide analog; antiviral drug (jams up polymerase)
What is a pyrimidine dimer?
two thymine bases block replication
What is the SOS system in bacteria?
SOS system allows bacterial cells to bypass the replication block with a mutation-prone pathway
What effect does UV have on DNA?
thymine dimer blocks DNA pol/bends helix then base substitution occurs
What are transposable elements?
sequences that can move about the genome
What is the order of the cell cycle?
Go phase, interphase, G1 phase, S phase, G2 phase, M Phase, prophase, pro metaphase, metaphase, anaphase, telophase, cytokinesis
