Cell Cycle and Meiosis – Flashcards
Unlock all answers in this set
Unlock answersquestion
How many chromosomes are in a human somatic cell?
answer
46
question
Are somatic cells haploid or diploid?
answer
diploid
question
Are germ cells haploid or diploid?
answer
diploid
question
Are sperm haploid or diploid?
answer
haploid
question
Are gametes haploid or diploid?
answer
haploid
question
What are the 2 phases of the cell cycle?
answer
interphase and mitosis
question
What are the parts of cell division
answer
PMAT and cytokinese
question
A certain cell that has 6 chromosomes in the G1 phase will have _____ chromosomes in the G2 phase.
answer
12
question
If a cell has 14 chromosomes at the start of prophase, how many will it have after cytokinesis?
answer
7
question
How is cell division different in animal and plant cells?
answer
animal: has centrioles and cleavage furrow plant: formation of cell plate
question
If a germ cell with 38 chromosomes undergoes meiosis, how many chromosomes will the resulting cells have? If a germ cell with 38 chromosomes undergoes meiosis, how many chromosomes will the resulting cells have?
answer
19, gametes
question
Meiosis divides one diploid cell into 4 _____ cells.
answer
haploid
question
A human sperm has _____ chromosomes.
answer
23
question
What is crossing over?
answer
Exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring
question
Summarize what happens during interphase?
answer
G1 S G2, DNA replication, preparing cell for mitosis
question
Why do cells divide instead of just getting larger? Be specific and explain how you could model this?
answer
bc of the surface area to volume ration cells divide instead of getting larger in order to ensure molecules can diffuse across the cell in a timely manner, could be modeled with dialysis tubing and a variety or molecules (iodine and starch)
question
Meiosis and sexual reproduction contribute to variation within a species. State the sources of variation in a these processes and why a species benefits from the variation that they allow for.
answer
crossing over, random movements of homologous chromosomes (independent assortment) and random fertilization contribute to variation, variation leads to increase survival of species
question
What is the first phase of meiosis? The last phase?
answer
prophase I, telophase II
question
In meiosis I, __________________ separate during anaphase I. In meiosis II, _______________ separate during anaphase II.
answer
homologous chromosomes, sister chromatids
question
What phase is skipped during meiosis?
answer
interphase after meiosis I
question
In which phase does crossing over occur?
answer
metaphase I
question
Chromosome #4 that you inherit from your mom and chromosome #4 that you inherit from your dad are said to be _________. When each of these chromosomes (#4 from your mom OR #4 from your dad) is duplicated, the two exact copies of each chromosome are called ___________
answer
homologous, sister chromatids
question
What is nondisjunction?
answer
gametes contain an abnormal/incorrect # of chromosomes due to failure of spindle fibers to separate or move more chromosomes during meiosis
question
Why do unicellular organisms need to undergo cell division?
answer
to reproduce
question
Why do multicellular organisms need to undergo cell division?
answer
to replace old and dying cells, or to repair
question
What is the role of growth factors?
answer
to trigger cell division from molecular signals
question
What is differentiation?
answer
when cells stop diving, specializes in structure and function
question
What is apoptosis?
answer
the process of eliminating unnecessary cells during development, removes unhealthy and damaged cells
question
What are cell cycle regulators?
answer
molecular signals either stimulating or halting divison
question
In general, what is the purpose of a checkpoint in the cell cycle?
answer
to make sure none of the DNA is damaged
question
What is one potential outcome when errors occur in this highly regulated cell cycle process?
answer
cancer can form
question
What type of protein that regulates the cell cycle is encoded by proto-oncogenes?
answer
stimulating proteins
question
What type of protein that regulates the cell cycle is encoded by tumor suppressor genes?
answer
inhibitory proteins
question
The most important cell cycle regulators are the ______
answer
cyclin-dependent kinases (CDKs)
question
What is kinase, and what does it do?
answer
enzymes that add a phosphate to other proteins to activate or inhibit their function—a process known as phosphorylation
question
When are the cyclin-dependent (CDKs) present inside the cell during the cell cycle?
answer
always
question
When are cyclins present inside the cell during the cell cycle?
answer
always
question
What do activated CDK-cyclin complexes do?
answer
they stimulate or inhibit cell cycle progression
question
Summarize what is happening in G1 phase
answer
cell increases in size and prepares to replicate its DNA
question
Summarize what is happening in S phase
answer
cell replicated DNA, at the end of the phase, cell has two sets of chromosomes
question
Summarize what is happening in G2 phase
answer
cell continues growth and prepares for divison
question
Summarize what is happening in mitosis overall
answer
cell stops growing and divides into two daughter cells
question
What three factors determine whether a cell enters G0 phase?
answer
development, type of cell, available resources
question
Name two reasons why cells can form tumors
answer
too much cell division, too little death
question
What cause uncontrolled cell division at the genetic level?
answer
mutations affecting proteins that normally regulate the cell cycle
question
Explain what occurs if the APC gene is mutated
answer
cells starts to accumulate because of struggle to differentiate
question
What do mutated proto-oncogenes cause?
answer
oncogenes (mutated proto-oncogenes) increase stimulation of cell cycle
question
What do mutated tumor suppressor genes cause?
answer
loss of inhibition, they decrease suppression
question
To cause cancer, proto-oncogenes require (1 or 2) allele(s) to be mutates and are therefore considered (dominate/recessive) This results in ___ of function.
answer
1, dominant, gain
question
To cause cancer, tumor suppressor genes require (1 or 2) allele(s) to be mutates and are therefore considered (dominate/recessive) This results in ___ of function.
answer
2, recessive, loss
question
Explain the impact on the cell cycle of proto-oncogene versus an oncogene
answer
proto-oncogenes are driving cell growth while oncogene are acting as an accelerator
question
Explain the impact on the cell cycle of one mutate tumor suppressor gene allele versus two mutated tumor suppressor gene alleles
answer
normal tumor suppressor genes act as breaks, but when broken, the cell cycle goes more quickly without break
question
When dies interphase occur?
answer
before meiosis
question
What occurs during interphase?
answer
cell duplicated DNA and prepares for mitosis
question
Uncoiled stringy DNA is called ___
answer
chromatin
question
DNA has ____ that determines traits of an organism
answer
genes
question
Different forms of a gene are called ____
answer
alleles
question
What are made during meiosis?
answer
gametes ie) sperm and eggs
question
Homologous chromosomes pair up during prophase I to form a ___
answer
tetrad
question
What happens in prophase during mitosis?
answer
DNA and proteins start to condense into chromosomes, nuclear envelope starts to break, microtubules are assembled and move one of two centriole pairs to opposite end of cells
question
What happens in metaphase during mitosis?
answer
all chromosomes line up at equator of spindle
question
What happens in anaphase during mitosis?
answer
attachment between two sister chromatids of each chromosome break, the two are now separate chromosomes that move to opposite spindle poles
question
What happens in telophase during mitosis?
answer
chromosomes de-condense, nuclear envelope is formed
question
What happens in cytokinesis during mitosis?
answer
two daughter cells are formed, each is diploid, it had two of each type of chromosomes.
question
What are somatic cells?
answer
replacement cells
question
What are germ cells?
answer
a cell lineage set aside for the formation of gametes (such as sperm and egg)
question
What are chromosomes?
answer
DNA molecules with its attached proteins
question
What are sister chromatids?
answer
duplicates of chromosomes
question
What is the centromere?
answer
small region with attachment sites for microtubules that move the chromosome during nuclear division
question
What are amoebas?
answer
free-living cells that do not leave interphase
question
What is a cleavage furrow?
answer
indentation in its plasma membrane
