Chapters 9-10 Flashcards
Name the three main stages of Interphase.
G1, S stage, G2
The G in G1 stands for growth. What is happening to cell size during this phase?
?
The G in G1 stands for growth. What is happening to the number of organelles in this phase?
The cell is making twice as many organelles
The S in the S phase is for synthesis. What exactly is happening to the DNA in the nucleus during this stage?
DNA replication produces another complete set of chromosomes
What new thing is being made in the cell during G2?
Proteins such as Microtubules
There are two important G stage controls. Where in interphase do they occur?
G1 checkpoint during the G1 phase and G2 checkpoint during the G2 phase
What is apoptosis?
Programmed cell death
How is where G1 and G2 occur related to apoptosis?
If the DNA isn’t being replicated, the cell cycle can be stopped and apoptosis can occur
What do tumor suppressor proteins do in general?
Inhibit the cell cycle
Are tumor suppressor proteins normal or do they only occur in cancer?
?
How are tumor suppressor proteins related to the control points?
?
Name two tumor suppressor proteins.
Telomeres and Proto-oncogenes
What is chromatin?
A tangled mass of loosely coiled threads; makes up chromosomes
Is chromatin Euchromatin or Heterochromatin?
Euchromatin
Is chromatin genetically active?
?
What are histones and how are they used to organize DNA?
Histones are proteins in eukaryotes that organize DNA
How are chromosomes made from DNA and histones?
?
Are chromosomes Euchromatin or Heterochromatin?
Heterochromatin
Is Heterochromatin genetically active?
Heterochromatin is not genetically active
During which stage of mitosis is chromatin organized into chromosomes?
Prophase
Where is the centromere on a chromosome?
A centromere is in the center of the chromosome holding the two sister chromatid together
How are sister chromatids related (Are they just copies of the same DNA)?
Sister chromatids are exact copies of a strange of DNA
Where are the kinetochores on a chromosome?
Kinetochores form on each side of the centromere in the center of a chromosome
What is the purpose of kinetochores?
Kinetochores pull the chromosome apart during the cellular division
What are centrioles?
A pair of barrel-shaped organelles
Are centrioles made of microtubules?
?
How many centrioles does it take to make a centrosome?
?
How many centrosome does a eukaryotic cell have?
Two
Are asters made of microtubules?
Yes they are an array of short microtubules
Does the Microtubule Organizing Center (MTOC) control the production of asters?
?
Do asters anchor the Microtubule Organizing Center (MTOC) to the cell wall during cell division?
?
What are spindle fibers?
Spindle fibers are protein structures that form early in mitosis, or cell division.
Are spindle fibers made of microtubules?
They consist of microtubules that originate from the centrioles, two wheel-shaped bodies located in the centromere area of the cell. The centromere is also known as the microtubule organizing center.
Are spindle fibers produced by the Microtubule Organizing Center (MTOC)?
Yes; They consist of microtubules that originate from the centrioles, two wheel-shaped bodies located in the centromere area of the cell. The centromere is also known as the microtubule organizing center.
What happens during Prophase? What is happening to the centrosomes? What is happening to the chromatin? What is happening to the nuclear membrane? What is happens to the nucleolus?
Centrosomes have duplicated and begin to migrate to the poles of the cell. Chromatin is condensing to chromosomes. The Nuclear envelope is breaking into fragments. The nucleolus disappears, centrosomes are closer to the poles, and spindle fibers are forming.
What happens during Prometaphase to the chromosomes?
The kinetochore of each chromatid is attached to a spindle fiber and chromosomes are moving to the center of the cell
What happens during Metaphase? Where are the chromosomes?
Chromosomes align at the center of the cell or the Metaphase plate and centrosomes are at the poles of the cell
What is the Metaphase plate?
An imaginary plane perpendicular to the spindle fibers of a dividing cell, along which chromosomes align during metaphase.
What moved the chromosomes during Metaphase?
?
What happens during Anaphase?
Sister chromatids are separated at the centromere and are pulled to the opposite side of the cell
Does Cytokinesis begin during Anaphase?
Yes Cytokinesis occurs during Anaphase and Telophase
What is Cytokinesis?
Cytokinesis separates the cytoplasm and organelles to daughter cells
What happens during Telophase?
Daughter cells are reforming the nuclear membrane and nucleoli reappear. Chromosomes uncoil to become chromatin. Cell gets ready for interphase activities.
Why is Telophase described as being just the opposite of Prophase?
The nuclear membrane and nucleoli are reforming instead of disappearing and chromosomes uncoil rather than coil up
Does Cytokinesis continue during Telophase?
Yes Cytokinesis occurs during Anaphase and Telophase
How are actin microfilaments involved in Cytokinesis?
Actin filaments constrict between the two daughter cells creating a cleavage furrow
What is a cleavage furrow?
A cleavage furrow indents the plasma membrane between two daughter nuclei and are created by actin filaments
In plants, the Golgi apparatus produces vesicles that align at the Metaphase plate. What do those vesicles contain? What is being constructed? What is the carbohydrate that is providing structure?
These vesicles release molecules that signal the formation of plant cell walls. The cell wall is being constructed. Cellulose is providing structure.
Do stem cells retain the ability to go through the cell cycle?
Stem cells retain the ability to divide and specialize
What is the stage called where most cells in adults stay and lose the ability to divide?
?
Where do bacteria and archaea keep their DNA?
Nucleoid region
Where is the bacterial DNA anchored? How does this help each new bacteria get the right amount of DNA after binary fission?
?
What are five characteristics of cancer?
- Lack differentiation
- Are immortal
- Have abnormal nuclei
- Don’t undergo apoptosis
- Lack contact inhibition
- Are invasive
- Undergo metagenesis and angiogenesis
Define proto-oncogene
Proteins coded for directly and indirectly stimulate the cell cycle
Define Tumor Suppressor gene
Proteins coded for directly inhibiting the cell cycle
Define telomere
Active in cancer and get shorter with each cell division and signal senescence
Define metastasis
?
What are homologous chromosomes or homologous pairs?
A set of chromosomes from either the ovum or sperm
What is a gamete?
Reproductive cells; 1n cells; ovum/sperm
Are gametes 2n or n?
1n
Are gametes diploid or haploid?
Haploid
How many chromosomes do human gametes have?
23
If synapsis means joined, when are homologous chromosomes joined? Why is this called bivalent?
Because there are two chromosomes
What is the function of the synaptonemal complex?
?
During Meiosis I what lines up at the metaphase plate?
Homologous chromosomes
What is crossing over? During which phase of Meiosis I does this occur?
Crossing over occurs when a gene from a sperm/ovum exchanges for the version of the same gene from the ovum/sperm. Crossing over occurs during Metaphase I.
During what phase do homologous chromosomes separate?
Anaphase I
When does interkinesis occur? What chromosomes are in the nucleus of a cell during interkinesis?
Interkinesis occurs between Meiosis I and Meiosis II
Are cells diploid or haploid during Metaphase II?
Haploid
During what phase do sister chromatids separate in Meiosis II?
Anaphase II
How many daughter cells are formed from one parent cell at the end of Meiosis II?
Four
What is the process of sperm formation and maturation called?
Spermatogenesis
What is the process of egg formation called?
Oogenesis
Compare the number of functional sperm produced by reduction division to the number of eggs (ovum) produced.
?
Define euploidy
The correct number of chromosomes
What is aneuploidy?
A change to euploid (the correct number of chromosomes)
How does nondisjunction result in aneuploidy?
One or two chromosomes fail to separate during meiosis resulting in a change of the correct number of chromosomes
What disorder is caused by nondisjunction of Chromosome 21?
Down Syndrome
How does no disjunction result in a female with Turner syndrome?
Failure of one or more chromosomes to separate during meiosis can result in a female with a genotype with only one X chromosome rather than two resulting in Turner syndrome
How does nondisjunction result in a male with Klinefelter syndrome?
A failure of one or more chromosomes to separate during meiosis can cause a male with a genotype with two or more X chromosomes.
What happens to a chromosome when there is a deletion? Are there diseases caused by deletions?
An end segment of a chromosome breaks off. Deletion may cause Williams syndrome and Cri du chat syndrome.
What happens to a chromosome when there is an inversion? Does this usually cause disease?
A segment that has become separated from the chromosome is reinserted at the same place but in reverse. Inversion may change gene activity.
What happens to a chromosome when there is a translocation? Are there diseases caused by translocation?
A segment is removed from one nonhomologous chromosome and inserted into another nonhomologous chromosome. Yes; Down syndrome, Alagille syndrome, and some cancers such as lurker lymphoma are caused by translocation.
