BIO EXAM #4
A human gamete contains how many chromosomes
-23
What is the difference in the DNA sequence of the normal individual and that of the individual with sickle cell anmeia.
-A single base has been changed
During which phase of meiosis I are bivalents segregated
-Anaphase I
What synthesizes the new DNA strand
-DNA polymerase
What protein cuts the damaged DNA strand
-UvrC
Which protein has a helicase function
-UvrD
What is the diference in the amino acid sequence of the normal individual and that of the individual with sickle cell aniema
-a single amino acid has been changed
When 2 haploid gametes unite they create a diploid cell called
-a zygote
After a tautomeric shift, in adenine
-adenine bonds with cytosine
Synapsis is the process of forming what
-bivalent
A nucleotide deletion in DNA replication will cause what
-causes the amino acids inserted after the deletion to be incorrect
Aneuploidy refers to an alteration in number of particular what
-chromosomes
UV light damages DNA by causing what
-covalent bonds to form between thymine nucleotides next to each other on the same DNA strand
What is the significant result of meiosis
-created haploid gametes for sexual reproduction
Which process invloves a physical exhange between chromosome segments of the bivalent
-crossing over
Which two key events occur at the beginning of meiosis but not mitosis
-crossing over -bivalent formation
Organisms pocessing chromosomes that occur in one or more complete sets are term what
-euploid
What is a tretraploid
-four chromosome sets per cell
The end result of meiosis II is
-four daughter cells that are haploid
A zygote is created when 2 haploid cells called what fuse
-gametes
During meiosis I was does it separate
-homologous chromosomes
In a tautomeric shift
-hydrogen atoms move from a nucleotide base with altered bonding properties
Polyploidy is generally a lethal condition in
-mammals
A diploid cell divides by a process called what to produce haploid cells
-meiosis
In a certain cell a pair of sister chromatids is attached to kinetchore microtubules from just one pole. This cell must be in
-meiosis I
crossing over during prophase occurs commonly in
-meiosis I
During what phase do homologous chromosomes allign along the center of the cell as bivalents
-metaphase I
The bivalents are organized along metaphase plate w their sister chromatids randomly alligned in a double row what phase of cell division is this
-metaphase of meiosis I
What describes an animal that is 2n-1
-monosomic
Trisomies 21, 18, 13, or abnormalities in the number of the sex chromosomes are most likely due to what
-nondisjunction
The nuleic acid sequence in mRNA is determined by what
-nucleotide sequence in DNA
What is a haploid
-one chromosome set per a cell
What two suffixes refer to a complete set of chromosomes
-ploid -ploidy
Unlike animals, plants often possess more than two sets of chromosomes. Plants ths exhibit what
-ployploidy
-In what phase of meiosis are the replicated chromosomes condense, the homologous chromosomes from bivalents and crossing over occurs
-prophase I
What metaphase I event provides a mechansim for vast genetic diversity
-random aligment
Because meiosis I produces 2 haploid nuclei it's called
-reduction division
The process by which two haploid gametes unite to form a zygote is called ______ reproduction
-sexual
Some of the characteristics of Trisomy 21 or Down syndrome are
-short structure -mental impairment -slanted eyes -flattened face
During anaphase II of meiosis blank are separated
-sister chromatids
What do mitosis and meiosis have in common
-sister chromatids are separated
What are the characteristics of meiosis II
-sister chromatids are separated -the resulting daughter cells are haploid -the sorting event is similar to that of mitosis
In prometaphase I of meiosis the nuclear envelope is completely broken down into vesicles and the what is entirely formed
-spindle apparatus
When a tautomeric shift occurs, the resulting nucleotide is an ______ of the nucleotide prior to the shift
-structural isomer
At what stage of meiosis I the joined pairs of sister chromatids have reached their respective poles and they have decondense
-telophase I
A mutation has occured that prevents the UvrA and UvrB from forming a complex. What result will this have on the damaged DNA
-the damaged DNA will not be recognized
A mutation has occured that has made UvrD non-functional. What result will this have on the damaged DNA
-the damaged segement of DNA will be recognized and cut, but will not be separated from the healthy strand.
If a frameshift mutation causes a stop codon to be inserted into the DNA sequence what will happen
-the resulting protein will be too short and non-functional
What are some characteristics of meiosis II
-the sorting event is similar to that of mitosis -sister chromatids are separated -the resulting daughter cells are haploid
What happens to the covalent bonds in light repair
-they're broken between the thymine dimers
What is triploid
-three chromosome sets per cell
What is a polyploid
-three or more chromosome sets per cell
True or false, a single point mutation in the DNA sequence leads to a change in the protein structure, which leads to a change in the proteins function and causes sickle cell anemia
-true
True or false, excision repair can be used to repair thymine dimers as well as other types of damaged DNA
-true
True or false, excision repair of thymine dimers is possiable because there are 2 strands of DNA
-true
What is a diploid
-two chromosome sets per cell
What is the end result of mitosis in a diploid organism
-two daughter cells that are diploid
How often does ultraviolet light result in the formation of thymine dimers
-ultraviolet light provides the energy for colvalent bond formation between 2 thymines
What is the correct order of meiosis I
1. Prophase I 2. Prometaphase I 3. Metaphase I 4. Anaphase I 5. Telophase I
Name the order of meiosis I starting from the earliest
1. replicated chromosomes condense from bivalents and crossing over occurs 2. nuclear envelope is completely broken down and spindle apparatus is entirely formed 3. bivalents are aligned along the center of the cell 4. homologous chromosomes separate and move toward opposite poles 5. chromosomes decondense and nuclear envelope reforms