August 23 Cell Ultrastructure and cytoskeleton

Question 1

What is the protoplasm made of

Answer 1

70-85% water; electrolytes, proteins, lipids, carbohydrates

Question 2

what is chromatin made of

Answer 2

DNA complexed with nucleoproteins

Question 3

what is karyotyping

Answer 3

sorting of chromosome pairs according to size and shape

Question 4

what is heterochromatin

Answer 4

electron dense, darkly staining, inactive DNA and nucleoproteins

Question 5

what is an example of heterochromatin

Answer 5

Barr body in females

Question 6

what is an example of euchromatin

Answer 6

dispersed DNA active in transcription (RNA synthesis)

Question 7

where can euchromatin be found

Answer 7

cells active in translation, they will have prominent nucleolus and lots of euchromatin

Question 8

why do we need RNA

Answer 8

because DNA cannot leave the nucleus to cytoplasm to be copied

Question 9

what type of chromatin mostly exists in the nucleus

Answer 9

heterochromatin

Question 10

what are lamp brush chromosomes

Answer 10

when active portions of chromosomes unravel to become visible

Question 11

where are nucleoproteins made

Answer 11

in the cytoplasm

Question 12

what are nucleosomes

Answer 12

segments of dna wrap around several histones

Question 13

what do nucleosomes do

Answer 13

regulate DNA activity

Question 14

what are non-histones

Answer 14

additional category of nucleoproteins may be involved in regulation of gene activity

Question 15

what are examples of nucleoproteins

Answer 15

histones, nucleosomes, and non-histones

Question 16

what are the inner and out nuclear membrane separated by

Answer 16

perinuclear cisterna

Question 17

describe the inner nuclear membrane

Answer 17

network of lamin filaments for support called nuclear lamina

Question 18

describe the outer nuclear membrane

Answer 18

studded with ribosomes

Question 19

what are the inner and outer nuclear membranes connected by

Answer 19

nuclear pore complex

Question 20

what is a nuclear pore complex

Answer 20

70-80 nm diameter channels surrounded by ring of proteins called nucleoporins

Question 21

what is the function of the nuclear pores in the nuclear membrane

Answer 21

regulate exchange of macromolecules between nucleus and cytoplasm

Question 22

what are ribsosomes

Answer 22

proteinaceous structures than contain rRNA

Question 23

where are ribosomes made and assembled

Answer 23

nucleolus

Question 24

where are ribosomes found

Answer 24

free in cytoplasm and attached to rER and outer nuclear membrane

Question 25

what types of cells do not have mitochondria

Answer 25

blood cells and skin cells (keratinocytes)

Question 26

what are cristae and what can be found on them

Answer 26

inner mitochondrial membrane pleated to form folds. lined with elementary particels that contain enzymes for oxidative phosphorylation

Question 27

what does the mitochodrial matrix contain and what do they do

Answer 27

dense granules which are thought to be binding/storage sites for Ca

Question 28

how are mitochondria similar to bacteria

Answer 28

they possess circular DNA and are self replicating by binary fission

Question 29

what is the endosymbiont theory

Answer 29

mitochondria are prokaryotes that were engulfed by another cell

Question 30

what are cytochromes and where are they located

Answer 30

enzymes on the inner membrane of cristae

Question 31

what are some functions of the sER

Answer 31

lipid synthesis, transport of proteins from rER to golgi, membrane formation and recycling. synthesis of cholesterol and steroid hormones and is principle organelle involved in detoxification and conjugation of drugs and toxins

Question 32

what are coated vesicles

Answer 32

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

Question 33

what are the functions of the golgi apparatus

Answer 33

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

Question 34

explain why the golgi is convex in form

Answer 34

there is a cis face and a trans face. proteins arrive from the rER in coated transfer vesicles at the cis face. proteins in clatharin coated vesicles for secretion leave the trans face giving rise to the addition of molecules to the cis face and subtraction of molecules from the opposing trans face

Question 35

vesicles in the golgi apparatus are bound for 3 places. what are those places and what are those vesicles called

Answer 35

1. secretory vesicles for extracellular use 2. membrane-bound vesicles for intracellular use 3. secretory granules for long term storage

Question 36

what is membrane trafficking and what organelle performs this

Answer 36

golgi appartatus, during exocytosis and secretion large amounts of intracellular membrane are incorporated into outer cell membrane and recycled by the golgi

Question 37

what are the 3 types of membrane bound vesicles

Answer 37

lysosomes, endosomes, and peroxisomes

Question 38

explain primary, secondary and tertiary lysosomes

Answer 38

primary- newly formed lysosomes produced by rER and golgi secondary- when the primary lysosome fuses with the phagocytic vesicle tertiary- hydrolytic breakdown of lysosome, resulting in a residual body

Question 39

what are endosomes

Answer 39

a type of endocytic vesicle with acid pH in lumen

Question 40

what are peroxisomes and what is their function

Answer 40

membrane bound organelles containing oxidases. they use enzymes, free radicals and hydrogen peroxide to oxidize toxic metabolites

Question 41

what are inclusions. be specific

Answer 41

non-living components of the cell such as neutral fat droplets, lipids, glycogen, granules, viral inclusions

Question 42

what are examples of intracytoplasmic pigments

Answer 42

melanin and lipofuscin

Question 43

where would lipofuscin be located

Answer 43

neurons