Exam 4 Flashcards
Long thin strands of DNA + protein
Chromatin
Is chromosome number higher, lower, or the same within a species?
The same
Cells with homologous pairs of chromosomes
Diploid
What are Homologs?
Chromosomes that occur in homologous pairs.
Organizes a rope of packed nucleosomes into tight loops
Scaffolding Protein
What does a DNA molecule consist of?
Nucleotides
Entire set of genes in an organism
Genome
What is the formation of the egg cell?
Oogenesis
What allows DNA to move through the cell without breakage and loss?
Chromosomes
What are homologs held together by?
Synaptonemal Complex
When cells are not dividing, what form is the DNA in?
Chromatin form
What is the formation of the sperm cells?
Spermatogenesis
Where are sister chromatids joined together?
Centromere
What cells have approx. 6 feet of chromatin?
Human Somatic cells
What are spindle fibers?
Microtubules
What is the name for the egg cell, plural and singular?
Ova (plural) and Ovum (singular)
What is the process of homologous pairs coming together?
Synapsis
Chromosomes with the same size, same structure, and genes for the same characteristics
Homologous Chromosomes
One homolog came from —-, the other homolog came from —-
Mom and Dad
What attaches to kinetochores?
Spindle Fibers
What is the only thing that might be different in homologous pairs?
The expression of the gene
Nucleosomes coiled like a rope
Packed Nucleosomes
DNA tightly looped and coiled to form a highly compact structure
Chromosomes
Homologous chromosomes occur only in what?
Diploid and higher ploidy levels
What is a kinetochore?
It is part of the centromere
What cells have approx. 3 feet of chromatin?
Human Gamete cells
What is the constricted area on a chromosome?
Centromere
Proteins that attach to DNA
Histones
The total number of chromosomes are always what?
An even number
What is a tetrad?
4 Chromatids
What is the formation of the gametes?
Gametogenesis
The exchange of chromatid segments between homologs
Crossing-over
What has only one chromosome from each homologous pair?
Haploid Cells
Histones are attached by what?
Opposite Charges
What is the Spindle Apparatus?
Microtubules that pull chromosomes through the cell during cell division
How many mammal species has been identified as polyploidy?
One
Characteristics of an organism are determined by what?
Genetic Information
Exact copies; the two identical strands of a single chromosome
Sister Chromatids
What does 2N stand for?
Diploid Number
What are body cells?
Somatic Cells
How many base pairs is 3 feet of chromatin?
3 billion base pairs
DNA thread between nucleosomes
Linker DNA
What does a nucleotide consist of?
- Phosphate
- Deoxyribose
- One of the 4 bases
Production of enzymes for mitosis occurs in what substage of interphase?
Gap 2 (G 2)
Chromosomes are only intact when?
During cell division
DNA is uncoiled as chromatin in what stage of the cell cycle
Interphase
What type of cells are diploid?
Somatic cells
Polyploid is rare in what?
Fish and amphibians
What does G1 stand for?
Gap 1
Events from one cell division to the next
Cell Cycle
What is deoxyribose?
A 5-carbon suger
Generally species with high chromosome number have — chromosomes?
Small
What are sex cells?
Gametes
What does N stand for?
Number of chromosome sets
Polyploid is most common in what?
Plants
How many base pairs is in 6 feet of chromatin?
6 billions base pairs
What are the mitosis stages?
Prophase, Metaphase, Anaphase, and Telophase
Somatic cells are all the cells except what?
Egg and Sperm
Describe the Interphase stage in Mitosis
- Stage when the cell is not dividing
- Longest stage of the cell cycle
- DNA is uncoiled as chromatin
- Nucleus intact; nucleolus present; nuclear intact
What determines traits?
proteins
What is the division of the nucleus?
Mitosis
Cells with one chromosome from each pair?
Haploid
Cells with more than two sets of chromosomes
Polyploid
What are tightly coiled and condensed chromatin?
Chromosomes
Group of 8 histones wrapped in a DNA
Nucleosome
Stage when the cell is not dividing
Interphase
What substage of interphase is when cells are permanently in G1 stage?
G0
Segment of DNA that codes for a protein.
Gene
What does 1N stand for?
Haploid Number
What are the protein strands connecting scaffolding proteins of the homologs.
Synaptonemal Complex
What are the 4 types of bases?
Adenine, Thymine, Guanine, and Cytosine
In mitosis what is the longest stage of the cell cycle?
Interphase
Are gametes haploid or diploid?
Haploid
What do pairs of homologs form?
Tetrad
What act like a spool for DNA?
Nucleosomes
What is permanently in G1 substage of interphase?
Nerves and Muscles
Division of the cytoplasm yielding two new cells
Cytokinesis
What are some environmental conditions that can affect the cell cycle?
Temperature, pH, and nutrition
What does the MTOC in animals consist of?
- Centrioles
- Pericentriolar material
- Asters
What has 2 divisions?
Meiosis
Describe the MTOC in animals
The MTOC is highly organized and structured
Highly organized, cylinder consisting of 9 sets of 3 microtubules per set
Centrioles
What are some external factors affecting the cell cycle?
- Contact Inhibition
- Environmental conditions
- Growth factors
Cells grow and new organelles are produced in what substage of interphase?
G1
Describe the MTOC in plants
The MTOC has a low level of organization with no distinct structure.
Daughter cells are genetically different from mother and from each other in what?
Meiosis
In meiosis what do the 2 divisions do?
1st division reduces chromosome number by 1/2, 2nd division seperates sister chromatids
What functions as a kinase only when it is bonded to cyclin?
Cyclin Dependent Kinase (Cdk)
How does the Cyclin/Cdk complex stimulate cell division?
- Activates proteins that promote cell division
- Inactivates proteins that inhibit cell division
What reduces chromosome number by 1/2?
Meiosis
What substage in interphase are the DNA in the form of single stranded chromatin
G1
What is “contact inhibition?”
Crowding/ noncrowding of cells
Some hormones can stimulate — and function as —
Cell Division and Growth Factors
What does Cdk stand for?
Cyclin Dependent Kinase
Extracellular substances produced by other cells that stimulate cell division
Growth Factors
Mitosis occuring without cytokinesis is common in what?
Some fungi
What are internal factors that control events in the cell cycle?
Cyclin and Cdk
What stimulates cell division?
Cyclin/Cdk complex
In interphase, cells are mostly in what stage?
G1
G2 stands for what when dealing with substages of interphase?
Gap 2
In what substage of interphase does DNA replicate and histones are synthesized?
Synthesis stage (S stage)
What produces gametes?
Meiosis
Form of cell division involved in growth and repair
Mitosis
When does cytokinesis occur in most plants and animals?
Telophase
Enzyme that activates or inactivates other proteins by phosphorylation
Kinase
There is no change in chromosome number in what?
Mitosis
What produces somatic cells?
Mitosis
Form of cell division involved in sexual reproduction?
Meiosis
What is produced when mitosis occurs without cytokinesis?
Multinucleate cells
What is the longest substage of interphase?
G1
New sister chromatids are formed in what substage of interphase?
Synthesis stage (S stage)
What does S mean when dealing with the substages of interphase?
Synthesis stage
Form of cell division associated with asexual reproduction
Mitosis
How long can a cell be in G1 substage of interphase?
Days, months, or years
How many unique gametes can each human produce?
Over 8 million
Daughter cells are exact copies of mother cell and of each other in what?
Mitosis
What produces 4 new cells?
Meiosis
What is Independent assortment?
The way one pair of homologs sorts into the gametes has no influence on other homologous pairs of chromosomes. The gametes will have one chromosome from each pair in all possible combinations
What does MTOC stand for?
Microtubule organizing center
There is no change in genetic information in what?
Mitosis
Exchange of chromatid segments between homologs
Crossing-over
What produces 2 new cells?
Mitosis
What are thread like proteins?
Fibrils
What has 1 division?
Mitosis
What is Cyclin?
A family of regulatory proteins
What are centrioles?
Highly organized, cylinders consisting of 9 sets of 3 microtubules per set
What is regulated by complex interactions of external and internal factors that form “checkpoints”?
Cell Cycle
What are the stages of meiosis (in order) and give detail of either 2N or 1N
Interphase (2N), Prophase I (2N), Metaphase I (2N), Anaphase I (2N), Telophase I (2N), Interkinesis, Prophase II (1N), Metaphase II (1N), Anaphase II (1N), Telophase II (1N),
– and — are one of the major sets of proteins acting as checkpoints in the cell cycle
Cyclin and Cyclin Dependent Kinase (Cdk)
The way one pair of homologs sorts into the gametes has no influence on other homologous pairs of chromosomes. The gametes will have one chromosome from each pair in all possible combinations
Independent Assortment
What are asters?
Short microtubules radiating out from the MTOC into the surrounding cytoplasm
Consist of thread like proteins called fibrils
Pericentriolar material
What do checkpoints do?
- Ensure conditions are right for cell division
- Ensure cell division is needed
- Ensure DNA is copied correctly during S substage
- Ensure sister chromatids have seperated during anaphase
2N goes to what in Meiosis?
1N
What changes concentration during the cell cycle?
Cyclin
Where are the major checkpoints in the cell cycle?
Between G1 and S; G2 and M; M and G1
Short microtubules radiating out from the MTOC into the surrounding cytoplasm
Asters
What bond with Cyclin Dependent Kinase to form Cdk
Cyclin
What are checkpoints?
Complex sets of proteins
What is pericentriolar material?
It consists of thread like proteins called fibris
What stage of meiosis might not occur?
Interkinesis
At what time in meiosis in females is where meiosis is still incomplete and is completed in response to contact with a sperm cell?
When released from the ovary
In what stage of meiosis do any traces of nuclei dissapear?
Prophase II
What forms a cleavage furrow?
Animal Cell Cytokinesis
In what stage of meiosis is there a very brief, interphase like stage?
Interkinesis
What pinches the cell into 2 new cells?
Animal Cell Cytokinesis
Single celled haploid and multicellular diploid
Animals
Cytokinesis differs between – cells and — cells
Plant Cells and Animal Cells
At what time in meiosis in females are where individual oocytes develop to become secondary oocytes and the first polar body; oocyte is at metaphase II in the secondary oocyte stage?
Beginning of puberty
In what stage of meiosis does synapsis occur?
Prophase I
Cells from meiosis become what?
Gametes
Multicellular haploid and multicellular diploid
Plants
In what stage of meiosis do chromosomes form from chromatin?
Prophase I
Cytokinesis is unequal; each division results in a viable cell with almost all the cytoplasm and a polar body which receives little or no cytoplasm and dies
Oogenesis
At what time in meiosis of the female are primary oocytes present and at prophase I?
At birth
In what stage of meiosis do spindle fibers form and attach to kinetochores?
Prophase I
In what stage of meiosis are sister kinetochores attached to spindle fibers from same pole
Metaphase I
What is the result of meiosis?
4 haploid cells
Multicellular haploid and single celled diploid
Some simple eukaryotes
In what stage of meiosis does the nuclear membrane dissolve?
Prophase I
In Oogenesis only one cell out of a potential of 4 cells from meiosis becomes what?
Egg cell (Ovum)
In what stage of meiosis are chromosomes lined up individually?
Metaphase II
In what stage of meiosis does tetrads line up on the midplane?
Metaphase I
In what stage of meiosis do chromosomes become single stranded?
Anaphase II
In what stage of meiosis does cytokinesis occur resulting in 2 new cells?
Telophase I
What is Cytokinesis?
Division of the cytoplasm
In what stage of meiosis are homologs pulled toward opposite poles
Anaphase I
In what stage of meiosis do centromeres split and sister chromatids seperate?
Anaphase II
In what stage of meiosis do double stranded chromosomes reach opposite poles?
Telophase I
(Just Read) Crossing Over process
In late prophase I, the synaptonemal complex dissolves which allows centromeres and most of the length of the homologs to seperate from each other. The homologs are still adhering to one another at isolated points along the length of the homologs. At these points the nonsister chromatids cross each other forming an X shape. At these locations the chromatids can break and join with the chromatid of the other homolog. The points where the chromatids cross one another are called chiasmata.
When does cytokinesis occur?
Telophase
In what stage of meiosis do new nuclei start to form?
Telophase II
In what process does actin protein filaments and myosin motor proteins collect around equator of cell and constrict plasma membrane
Animal Cell Cytokinesis
The points where the chromatids cross one another
Chiasmata
In what stage of meiosis does crossing over occur?
Prophase I
What process forms a cell plate?
Plant Cell Cytokinesis
What are the proteins involved in muscle contraction?
Actin and Myosin
In what stage of meiosis might have a slight tendency to form new nuclei?
Telophase I
In what process does the cell plate develop into a cell wall?
Plant Cell Cytokinesis
Does Animal Cell Cytokinesis or Plant Cell Cytokinesis have a rigid wall?
Plant Cell Cytokinesis
1N cells can go through mitosis in some organisms such as —,— and —
Fungi, protists, and a very limited set of plants
In what process do vesicles from Golgi Complex fuse together across middle of cell; vesicles contain cell material
Plant Cell Cytokinesis
