Ch. 2 Flashcards
If a species has a haploid number of 16 chromosomes, how many chromosomes would be in a diploid cell from this organism?
32
Having two copies of the same genome are said to be
diploid
Having one copy of the genome are
haploid
Self-renewal of cells
Stem cells are diploid cells that divide to give rise to differentiated cells
Endoplasmic Reticulum
Rough ER: has ribosomes
Smooth ER: no ribosomes
protein synthesis & folding; lipid synthesis
Golgi Apparatus
Stacks of membrane-enclosed sacs, sugar made and linked to starches or joined to lipids or proteins; proteins finish folding; secretions stored
Lysosome
Sac containing digestive enzymes; degrades debris; recycles cell contents
Mitochondrion
2 membranes; inner membrane enzyme-studded; release energy from nutrients
Nucleus
porous, double-membrane sac containing DNA; separates DNA within cell
Peroxisome
Sac containing enzymes; breaks down and detoxifies various molecules
Ribsome
2 associated globular subunits of RNA and protein; scaffold and catalyst for protein synthesis
Vesicle
membrane-bounded sac; temporarily stores or transports substances
MNGIE is a rare autosomal recessive human disease characterized by intestinal and ophthalmologic abnormalities. It occurs due to a mutation that leads to inadequate energy production in affected cells.
Which organelle’s function do you predict is affected in MNGIE?
Mitochondria
Cutis laxa is a connective tissue disorder. One of the causes is abnormal glycosylation of serum proteins. Glycosylation is the addition of a carbohydrate such as a sugar to another molecule.
Which organelle do you predict is affected in cutis laxa?
Golgi Apparatus
Mitochondrial DNA (mtDNA)
37 genes, maternal inherited
Plasma Membrane
bind ligands that may set into motion a cascade of chemical reactions inside the cell (receptors that extend from plasma membrane)
Signal Transduction
molecules form pathways that detect signals from outside the cell and transmit them inward
Cellular Adhesion
plasma membrane helps cells attach to certain other cells
Parts of the plasma membrane
selectively-permeable phospholipid bilayer forming the boundary of the cells
- outside - hydrophilic, touches body fluid
- inside - hydrophobic, stacked together
- contains proteins penetrating membrane
- more cholesterol, membrane more rigid
How many phases in cell cycle?
4 phases:
Interphase: G1, S, G2,
M
Interphase
Chromosomes are uncondensed
G0
a quiet phase, proceed to division, remain specialized, cell death
*most cells stay in G0 phase
G1
before DNA synthesis begins –> preparing cell for mitosis
- making of organelles, increase in cell size
S phase
DNA is replicated
G2
portion of interphase after DNA synthesis occurs
Chromosomes form in what phase of the cell cycle?
mitosis
Mitosis
Prophase
Metaphase
Anaphase
Telophase
Cell Cycle Checkpoints
DNA Damage Checkpoint @ G1
Slow checkpoint @ S phase
DNA Damage Checkpoint @ G2
Apoptosis Checkpoint @ G2 before mitosis (if survivin accumulates, mitosis ensues)
Spindle Assembly Checkpoint @ metaphase & anaphase
If survivin accumulates, mitosis will occur at
Apoptosis Checkpoint
Inhibits cell cycle until DNA can be repaired
DNA damage checkpoint
Checks if the spindle is built and chromosomes are attached to the spindle
Spindle assembly checkpoint
Telomeres
located @ the ends of chromosomes, the longer they are the younger it is, lose 50-200 endmost bases after each division until the 50th division
*telomerase: sperm, eggs, bone marrow, and cancer cells produce to prevent shortening of telomeres (heterochromatin, repeat)
After DNA replication copies of the genome are joined at
centromeres
Long strands of chromosomal material in replicated chromosomes are called
chromatids
Centriole microtubules join with other proteins to organize the spindle in structures called
centrosomes
Chromosome tips are called
telomeres
Select the sources of human stem cells.
embryonic stem cells, induced pluripotent stem cells, adult stem cells (multipotent)
*progenitor cells do not have the capacity of self-renewal
Stem cells
divide by mitosis, produces 2 daughter cells (stem cell & progenitor cell) which may be partially specialized
stem cells -> other specialized cells (differentiation)
A cell that can give rise to every cell type
Totipotent
A cell that cannot give rise to every cell type but still has a large number of possible fates
Pluripotent
A cell that has only a few developmental choices
Mulitpotent
