1: Animal Cells and the Cell Cycle Flashcards
selectively permeable phospholipid bilayer
plasma membrane
added or removed to change flexibility in plasma membrane
cholesterol
facilitate transport of polar molecules/ions/serve as receptors
glycoproteins
system of microtubules and microfilaments that provide structural support and facilitate movement
Cytoskeleton
facilitate cellular locomotion
(actin, myosin)
microfilaments
facilitate the movement of molecules and organelles through the cytoplasm and mRNAs from the nucleus to the cytoplasm
microtubules
folds cells together and resist cell stretching
intermediate filaments
filament sizes (smallest to largest):
microfilaments < intermediate filaments < microtubules
microtubule organizing center found near nucleus; contain pair of centrioles made up of microtubules used in cell division
centrosome
- holds cell’s DNA
- surrounded by double membrane nuclear envelope w pores
- site of DNA replication and transcription
Nucleus
- site of cellular respiration
- produce ATP to fuel cell
- possess a small genome w functions restricted to mitochondrion
mitochondria
- modifies proteins
- synthesizes lipids w/in nucleus
endoplasmic reticulum
modifies proteins synthesized by ribosomes
rough ER
lacks ribosomes; synthesizes carbohydrates and lipids
smooth ER
- site of protein synthesis
- found w/in cytoplasm
- can be attached to rough ER
ribosomes
- digest/break down materials in the cell
- destroy pathogens
lysosomes
- oxidize/break down fatty acids, amino acids
- detoxify toxic molecules
peroxisomes
transport, package, distribute lipids and proteins throughout cell
golgi apparatus
- motile extensions of cell surface
- used for cell locomotion/sweeping materials past cell
cilia and flagella
- extended cytoplasmic processes that facilitate amoeboid movement
- can be used to engulf materials/ other cells
pseudopodia
3 methods of transport
diffusion, mediated trasport, endocytosis
type of transport:
- passive movement from an area of higher conc to lower conc
- may occur through membrane or gated ion channels
diffusion
type of transport:
molecules move through membrane w aid of transporter/carrier protein
carrier mediated
type of transport:
ingestion of material by the cell
endocytosis
3 types of endocytosis
pinocytosis, phagocytosis, receptor-mediated endocytosis
- nuclear division of chromosomes/ somatic cells
- results in 2 diploid daughter cells
mitosis
- division of cytoplasm
- usually follows mitosis
cytokinesis
nuclear division of sex cells
meiosis
- phase where cells are not actively dividing
- DNA replication and protein/RNA synthesis occur
- takes up majority of cell cycle
interphase
- preparation for DNA replication
- tRNA, ribosomes, mRNA, enzymes synthesized
G1 phase
- DNA replication occurs
- typically lasts 6 hours in mammalian cells
S phase
- preparation for cell division
- spindle and aster proteins are synthesized
G2 phase
- centrosomes, centrioles replicate + migrate to opposite poles
- nuclear envelope disintegrates
- spindle formed via microtubule assembly
- chromatin condenses to chromosomes
prophase
form from microtubules binding to kinetochores by radiating from the centrosome
asters
region in the middle of nuclear area
metaphase plate
condensed sister chromatids move to metaphase plate
metaphase
- cohesin proteins removed
- kinetochore microtubules pull chromosomes to opposite poles
- cell elongates
anaphase
- daughter chromosomes crowded tgt
- microtubules disassembled
- chromosomes become chromatin again
- nuclear envelope reforms
telophase
- cleavage furrow appears by actin binding proteins
- infolding edges meet/fuse = 2 separate cells
cytokinesis
- 2 successive mitotic divisions
- genetic material is replicated once followed by 2 rounds of division
- result: 4 haploid daughter cells
meiosis
- homologous chromosomes paired (synapsis) = bivalents
- crossing over occurs
prophase 1
when nonsister homologous chromosomes exchange segments
crossing over
- bivalents align at metaphase plate
- random alignment
metaphase 1
bivalents move to opposite poles
anaphase 1
- separated chromosomes at opposite poles
- = one of each homologous pair in each daughter cell
telophase 1
occurs when homologous chromosomes fail to separate
nondisjunction
the addition or deletion of sets of chromosomes
aneuploidy
enzymes that mediate during transitions between phases
cyclin-dependent kinases
protein subunits that activate cdk’s
cyclins
- programmed cell death
- occurs when damage from oxidizing agents accumulates
- necessary to maintain health
apoptosis
earliest organisms
anaerobic prokaryotes
what introduced oxygen into the atmosphere
evolution of photosynthesis in cyanobacteria
earliest life may have existed as early as…
3.5 GYA
first great increase of oxygen was…
2.4 GYA
theory that mitochondria and chloroplasts originated from aerobic and photosynthetic bacteria living w/in larger cell
endosymbiosis
