Cell Reproduction Flashcards
True or false: somatic and reproductive cells reproduce differently
true
What is generated during somatic cell division?
two genetically identical cells
How many chromosomes does a somatic cell have?
48
What is the division of the nucleus in somatic cell division called?
mitosis
What is generated during reproductive cell division?
produces gametes (sperm and egg), 4 non genetically identical cells
How many chromosomes do gametes have?
23
What is the division of the nucleus in reproductive cell division called?
meiosis
What is the division of the cytoplasm called?
cytokinesis
What are somatic cells that contain 23 pairs of chromosomes called?
diploid (2n) cells
What are homologous chromosomes?
the two chromosomes of the pair, they look very similar
What is different about sex chromosomes?
designated X (large), Y (small)
What is a female sex chromosome?
XX
What is a male sex chromosome?
XY
What does a somatic cell go through in its life cycle?
interphase and mitotic (m) phase
What is the cell cycle?
conventionally the interphase and mitotic phase of a somatic cell can be fit into a 24 hr cycle
What is G0 phase of interphase?
cells stay in G1 phase for a long time and may not reproduce, the exit cycle and stay in G0 phase
Give examples of body cells arrested in the G0 phase
skeletal muscle cell, neurons
What are chromatids?
the chromosomes during the mitotic prophase become visible as a pair of identical strands
What is a centromere?
it holds the chromatid pair together
When do the nuclear envelope and the nucleolus disappear during mitosis?
later in prophase
During metaphase what is aligns the centromeres of the chromatid pairs at the centre of the cell?
mitotic spindle
What is the visible alignment of the chromatid pairs in the middle of the cell during metaphase called?
metaphase plate
What is the main thing that happens in anaphase?
chromosomes move to opposite poles of the cell
How are chromosomes formed during mitotic anaphase?
centromere split separating the chromatid pair to form the chromosomes
When does mitotic telophase begin?
after chromosomal movement stops
When does mitotic telphase stop?
when cytokinesis is completed
What happens during cytokinesis?
begins in late anaphase forming the cleavage furrow pulls the plasma membrane inward
What is a cleavage furrow?
a contractile ring that pulls the plasma membrane inward during cytokinesis, it is always perpendicular to the mitotic spindle
What begins once cytokinesis is completed?
interphase
What is the nuclear division of reproductive cells called?
meiosis
How many chromosomes do gametes contain?
23
What types of cells are gametes?
haploid (n)
When does Meiosis I begin?
after the chromosomal replication is completed
How does prophase I differ from mitotic prophase?
two sisters of chromatids of each homologous chromosome pair off and form a tetrad, the parts of chromatids within treads may be exchanged with one another in a process called crossing over
What is a tetrad?
four chromatids
what does crossing over result in?
genetic recombination which accounts for a large variety of the genetic pool of gametes
What is crossing over?
part of the chromatids of two homologous chromosomes may be exchanged with one another
When do tetrads line up along the metaphase plate?
metaphase I
What happens during anaphase I?
the members of each homologous pair separate and are pulled to opposite poles of the cell, paired chromatids do not split, the remain together
Each resulting cell of Meiosis I has _______(_) number of chromosomes
haploid (n)
True or false: after meiosis I each cell contains only one member of each pair of the homologous chromosomes present in the starting cell
true
True or false: meiosis II is similar to mitosis
true
What is the net result of meiosis II?
four haploid cells genetically different from starting diploid cell
What are the three possible destinies of cells?
remain alive and functional w/o dividing, grow and divide, or die
What keeps the balance between cell proliferation and cell death?
homeostasis
What within a cell can activate a protein for functioning?
enzymes cyclin-dependent protein kinases (Cdk’s)
What within a cell can deactivate a protein?
enzymes
What is the activation of Cdk’s at the appropriate time crucial for?
DNA replication, mitosis, cytokinesis
What switches Cdk’s on and off?
cellular proteins called cyclins
What is apoptosis?
the normal type of cell death and does not trigger inflammation
What is necrosis?
pathological cell death and results from tissue injury and triggers inflammation
What is gerontology?
the scientific study of the process and problems associated with aging
What is geriatrics?
the branch of medicine that deals with the medical problems and care of elderly persons
What is cessastion of mitosis?
normal cells can divide only for a certain number of times and then stop, a normal genetically progemmed event
What are telomeres?
They are DNA sequences found at the tips of chromosomes, they protect the chromosomes from erosion and sticking to each other
What happens to telomeres after each cycle?
shorten after each cell cycle
With age why do tissues lose elasticity and stiffen?
glucose is madded to intracellular and extracellular proteins and this links adjacent proteins and with age more cross-links are formed
