Cells 🧫

Question 1

Nucleolus

Answer 1

Ribosomal RNA synthesis (all subunits except 5S)

Question 2

Mitochondrion

Answer 2

Semi-autonomous (own genes; independent replication via binary fission)

Outer/inner membrane//inter membrane space//cristae//matrix

ETC + ATP synthase = oxidative phosphorylation —> power

Release ETC enzymes = initiate apoptosis

Question 3

Golgi

Answer 3

Stacked membranous discs

Further processing of proteins (+carbs/P/S/FA tails/specific signal sequence)

Re-package vesicles and ship out (intra/extra cellular targets and PM)

CIS vs TRANS GN

Question 4

R Endoplasmic Reticulum

Answer 4

Contiguous with nuclear envelope; ribosomes for protein translation

Question 5

S Endoplasmic Reticulum

Answer 5

Contiguous with nuclear envelope but NO ribosomes

Protein transport to Golgi

Lipid Synthesis

Detoxification

Question 6

Lysosome

Answer 6

Hydrolytic enzymes for breakdown of substrates from endocytosis and cellular waste/old organelles (autophagy)

Enzyme release breaks down cell = autolysis or direct apoptosis

Question 7

Peroxisome

Answer 7

“Da PPP”

H2O2 breakdown of very long chain fatty acids to shorter long chain fatty acids via B oxidation (also D- amino acids)

Help synthesize phospholipids

Contain some enzymes of Pentose Phosphate Pathway

Question 8

Centriole

Answer 8

Located in centrosome region

9 TRIPlets of mt @ HOLLOW center

Organizing center for microtubule attachment, migration to opposite poles, organize mitotic spindle for sister chromatid separation during cell division

Question 9

Intermediate Filaments

Answer 9

Diverse family of proteins, cell type dependent (keratin, desmin)

Cell to cell and cell to ECM adhesion (adherens junctions; desmodomes)

Maintain cellular shape

Tension bearing —> rigid structure

Anchor organelles/synaptic machinery

Question 10

Microtubule

Answer 10

Hollow tubulin polymers in 9 + 2 doublet arrangement (euk)

Vesicular transport via dynein/kinesins in axons and cell bodies

Movement (cilia — across cell surface) (flagella — cell itself)

Attach to centrioles and chromosomes in mitosis to pull apart sister chromatids at kinetochores

Question 11

Microfilaments

Answer 11

Polymerized actin rods arranged in bundles and networks

Protect cell integrity

Form cleavage furrow in mitosis (ring of microfilaments contracts in cytokinesis until cells pinch off)

Movement (actin + mysosin + ATP = muscle contraction)

Question 12

Archaea

Answer 12

Prokaryotes (single cell, non membrane organelles)

Visually like bacteria (single circular chromosome, •/• binary fission/budding, similar structure)

Eukaryotic similarities (start translation with Met, similar RNA pol, histone association)

Many extremophiles (High T/salinity // no light) but many habitats including human body

Alt E sources via inorganic chemosynthesis (N/S)

Question 13

Plasmid

Answer 13

Extrachromosomal/genomic circular DNA in bacteria

Confer benefit or virulence F such as resistance, toxin production, adhesion, evasion

Question 14

Episome

Answer 14

Plasmid that can integrate into bacterial genome

Question 15

Transformation

Answer 15

Integrate foreign to host genome

Frequently from nearby bacterial lysis

Common in gram negative rods

Question 16

Conjugation

Answer 16

Bacterial sex!(ual) production

Male donor (+) with sex factor (plasmid coding for sex pili formation) forms conjugate bridge with (-) recipient female for UNIdirectional transfer of genomic material including sex factor thereby making (-) become (+) and capable of transferring to other bacteria in the colony

If sex factor integrates into genome, will attempt to transfer entire circular chromosome (bridge will usually fail before total transfer) = Hfr or High frequency recombination, can adapt very quickly

Question 17

Transduction

Answer 17

Vector transfers bacterial DNA

Typically bacteriophage that releases trapped bacterial DNA into new host cell

Question 18

Transposons

Answer 18

Insert AND remove from genome

Not limited to prokaryotes

Question 19

Positive Sense RNA Virus

Answer 19

Single stranded RNA directed translated by host ribosome in cytoplasm

Question 20

Negative Sense RNA Virus

Answer 20

Single stranded RNA template; must first make complementary strand with VIRAL RNA replicase in host cytosol, then host ribosomes translate

Question 21

Retrovirus

Answer 21

Enveloped ss RNA with 2 identical RNA molecules that VIRAL RNA transcriptase uses to synthesize ss DNA that integrates into host DNA

May remain dormant in host for multiple replication cycles before environmental factors trigger expression via usual cellular transcription/translation machinery

Examples: HPV and HIV

Question 22

Lytic Cycle

Answer 22

Abundance of viral progeny produced by host cell leads to cell lysis and no further ability to use cellular machinery

Infected host = virulent

Question 23

Lysogenic Cycle

Answer 23

Integrated viral DNA is not immediately expressed but remains dormant during multiple cycles of host cell replication until environmental factors cause provirus to leave the genome and begin progeny formation at which point cell is virulent and considered to be in the lyric phase of viral replication