Cell Ultrastructure

Question 1

what are the 2 major categories of organisms?

Answer 1

prokaryotes and eukaryotes

Question 2

Examples of prokaryotes

Answer 2

Monera, cyanobacteria

Question 3

examples of eukaryotes

Answer 3

single-celled protists, protozoa and multicelled metazoans

Question 4

Protoplasm

Answer 4

contained in cells, (~70-85% water; electrolytes, proteins, lipids, carbohydrates)

Question 5

cytoplasm

Answer 5

semi-liquid contents between cell membrane & nuclear membrane, surrounds organelles

Question 6

nucleoplasm

Answer 6

within nucleus

Question 7

Chromosomes

Answer 7

DNA complexed with nucleoproteins to form chromatin

Question 8

alleles

Answer 8

different forms of same gene

Question 9

Hererochromatin

Answer 9

electron-dense, darkly-staining, inactive DNA & nucleoproteins
•In females, permanently inactive DNA aka Barr bod
•Represents degenerate X chromosome; only 1 of pair active, other degenerates

Question 10

Euchromatin

Answer 10

dispersed DNA activein transcription (RNA synthesis)
Cells active in translation—within (protein synthesis in cytoplasm) will have prominent nucleolus& abundant euchromatin
RNA provides “working copies” of DNA

Question 11

what is the most chromatin in nucleus?

Answer 11

inactive heterochromatin

Question 12

lamp brush chromosomes

Answer 12

Active portions of chromosomes unravel to become visible

Question 13

Histones

Answer 13

most of DNA-associated protein in eukaryotesAssist with DNA folding => chromatin organization into chromosomes

Question 14

nucleosomes

Answer 14

segments of DNA wrap around several histones; regulate DNA activity

Question 15

non-histones

Answer 15

may also be involved in regulation of gene activity

Question 16

what separates the inner and outer nuclear membrane?

Answer 16

perinuclear cisterna

Question 17

how is the inner and outer nuclear membrane connected

Answer 17

nuclear pore complex surrounded by nucleoporins

Question 18

inner nuclear membrane

Answer 18

associated with network of lamin filaments for support called nuclear lamina

Question 19

outer nuclear membrane

Answer 19

studded with ribosomes, continuous with rER

Question 20

ribosomes

Answer 20

bipartite, proteinaceous structures (contain rRNA), synthesized & assembled in nucleolus, site of protein synthesis

Question 21

what are the mitochondria NOT present in?

Answer 21

RBC and keratinocytes

Question 22

within the mitochondria, the inner membrane has cristae which is lined with what?

Answer 22

elementary particles that contain enzymes for oxidative phosphorylation

Question 23

what does the mitochondria matrix contain?

Answer 23

dense granules thought to be binding/ storage sites for Ca

Question 24

how does the cell depend on energy and where does it begin?

Answer 24

cellular respiration; in the cytosol where glucose converted to pyruvic acid

Question 25

where does anaerobic glycolysis occur

Answer 25

cytoplasm

Question 26

where does aerobic respiration occur

Answer 26

mitochondria; where the the matrix contains Kreb cycle

Question 27

where is the most ATP produced?

Answer 27

oxidative phosphorylation by cytochromes of electron transport system (ETS)

Question 28

Cytochromes

Answer 28

enzymes on inner membrane of cristae

Question 29

Endoplasmic reticulum

Answer 29

series of membranous sheets and tubules throughout cytoplasm

Question 30

rER

Answer 30

surface receptor molecules for ribosomal attachment, protein synthesis

Question 31

sER

Answer 31

lipid synthesis, transport proteins from rER to golgi, membrane formation and recycling

Question 32

coated vesicles in ER

Answer 32

surround and coat proteins for transport, bud off sER, transport proteins between sER & Golgi & between golgi & cell surface

Question 33

Golgi apparatus

Answer 33

post-translational modification, packaging & sorting of proteins synthesized in rER

Question 34

what Golgi network is convex?

Answer 34

cis= forming face; proteins arrive from rER in coated transfer vesicles

Question 35

what golgi network is concave?

Answer 35

trans= maturing face; proteins packaged into clathrin-coated vesicles for secretion

Question 36

how do vesicles bud off maturing face?

Answer 36

condensing vacuoles, sorted into secretory vesicles for extracellular export via exocytosis or membrane-bound vesicles for intracellular use, or as secretory granules for long term storage

Question 37

membrane trafficking

Answer 37

during exocytosis & secretion, large amounts of intracellular membrane incorporated into outer cell membrane-- recycled by golgi

Question 38

types of membrane- bound vesicles

Answer 38

lysosomes, endosomes, peroxisomes

Question 39

lysosomes

Answer 39

contain hydrolytic enzymes

Question 40

1' lysosomes

Answer 40

inactive, newly formed produced by rER and golgi

Question 41

what happenes when 1' lysosomes fuse with phagocytic vesicles (or phagosomes)?

Answer 41

become phagolysosomes= 2' lysosomes

Question 42

3' lysosome

Answer 42

residual body, hydrolytic breakdown results in production; excreted or remain in cells for life

Question 43

autophagy

Answer 43

programmed cell death

Question 44

endosomes

Answer 44

type of endocytic vesicle with acid pH in lumen

Question 45

example of endosomes

Answer 45

proton pumps, which pump H+ into interior, acidifying contents

Question 46

peroxisomes

Answer 46

microbodies, membrane-bound organelles containing oxidative enzymes (oxidases); resemble lysosomes---also contain catalase and peroxidase

Question 47

how do peroxisomes oxidize toxic metabolites

Answer 47

use enzymes, free radicals, and hydrogen peroxide

Question 48

inclusions

Answer 48

- non-living components of cell | - neutral fat droplets, lipids, glycogen, secretory & pigment granules

Question 49

viral inculsions

Answer 49

intracytoplasmic or intranuclear

Question 50

types of intracytoplasmic pigments?

Answer 50

melanin and lipofuscin

Question 51

melanin

Answer 51

black, brown, granular pigment; produced by melanocytes, transported to other cells

Question 52

lipofuscin

Answer 52

gold-brown granules; frequently seen in neurons; sometimes called “old age pigment”