Unit 1 Cell Structure

Question 1

3 basic parts of human cells

Answer 1

plasma membrane
cytoplasm
nucleus

Question 2

cytoplasm

Answer 2

made up of cytosol and cytoskeleton

Question 3

plasma membrane

Answer 3

dynamic barrier
maintains gradients
phospholipid bilayer

Question 4

plasma membrane proteins

Answer 4

integral
extrinsic (peripheral)
glycoproteins

Question 5

integral proteins

Answer 5

extend through entire membrane

transmembrane proteins

Question 6

extrinsic proteins

Answer 6

associated with cytoplasmic or extracellular region

Question 7

glycoproteins

Answer 7

covalently linked sugar residues outside the cell
act as recognition sites
self determinant for immune system

Question 8

functions of membrane proteins

Answer 8

transport
enzymic activity
receptors
intercellular joining
cell-cell recognition
attachment

Question 9

organelles

Answer 9

nucleus
endoplasmic reticulum
Golgi complex (apparatus)
lysosomes
mitochondrion
peroxisomes
ribosomes

Question 10

nucleus function

Answer 10

1. partitioning of DNA
2. replication of DNA
3. transcription of DNA to RNA
4. ribosome assembly

Question 11

nuclear envelope

Answer 11

double membrane, continuous with ER

nuclear pores

Question 12

DNA

Answer 12

double helix, stabilized by H-bonding between bases
chromatin
most highly condensed during mitosis

Question 13

chromatin

Answer 13

DNA packaged with histone proteins

Question 14

heterochromatin

Answer 14

densely coiled, less active

Question 15

euchromatin

Answer 15

less dense, transcriptionally active

Question 16

nucleolus

Answer 16

site of synthesis/organization of ribosomes

Question 17

nucleolus organization

Answer 17

1. nucleolar organizer, encodes DNA
2. pars fibrosa - rRNA
3. pars granulosa - maturing ribosomes (RNA + proteins)

Question 18

endoplasmic reticulum (ER)

Answer 18

interconnected network of tubular membranes and flattened sacs; continuous with outer membrane of nuclear envelope

Question 19

rough ER

Answer 19

surface has many ribosomes; cisterna
site of protein synthesis
growing polypeptide chain glycosylated and released in lumen
proteins packaged and released

Question 20

smooth ER

Answer 20

no ribosomes or protein synthesis
synthesis of lipids and steroids
glycogen metabolism
detoxification, xenobiotics

Question 21

sarcoplasmic reticulum

Answer 21

sequesters and releases calcium ions in muscle

Question 22

Golgi complex (apparatus)

Answer 22

continuation of ER; stacks of flattened sacs; cisternae
processing and packaging of proteins
completes glycosylation
carries out other protein modifications

Question 23

Golgi complex polarity

Answer 23

cis face - receiving side - fuses with vesicles released from RER
trans face - shipping side - proteins secreted bound for cell membrane

Question 24

lysosomes

Answer 24

form by budding off Golgi
contains hydrolytic enzymes (lipases, proteases, nucleases, and carbohydrases)
acidic environment (H+ pump)

Question 25

lysosome function

Answer 25

immunological defense
cellular recycling
apoptosis

Question 26

mitochondrion

Answer 26

double membrane
enzymes of TCA cycle and beta-oxidation of fatty acids
semi-autonomous (contains its own DNA

Question 27

cristae

Answer 27

folded inner membrane of mitochondrion

contains carrier proteins of electron transport system and ATP synthase

Question 28

peroxisome function

Answer 28

contain enzymes for detox:
oxidases - free radicals, etc release H2O2
catalases - converts H2O2 to water and oxygen
oxidize long chain fatty acids

Question 29

peroxisome structure

Answer 29

resemble lysosomes

may stain darker due to enzymes

Question 30

ribosomes

Answer 30

protein synthesis

Question 31

free polyribosomes

Answer 31

proteins for cytoplasm

Question 32

bound polyribosomes

Answer 32

proteins for outside cell

Question 33

cytoskeleton functions

Answer 33

cell shape and framework
binding sites for organelles
cellular movement
cellular specializations

Question 34

cytoskeleton composition

Answer 34

microtubules (largest)
microfilaments (smallest)
intermediate filaments

Question 35

microtubules composition

Answer 35

tubulin
heterodimers
protofilaments
may form as singlets, doublets, or triplets

Question 36

tubulin

Answer 36

globular proteins

Question 37

heterodimers

Answer 37

alpha and beta tubulin

Question 38

protofilaments

Answer 38

assembly of heterodimers

Question 39

centrioles

Answer 39

structures composed of 9 triplets crosslinked

Question 40

centrosome

Answer 40

2 centrioles perpendicular to each other

Question 41

axoneme

Answer 41

9 doublets + 2 singlets

form cilia and flagella

Question 42

microtubule function

Answer 42

cellular trafficking
movement of chromosomes
movement of extracellular materials (cilia)
movement of sperm (flagella)

Question 43

microfilament composition

Answer 43

g actin

f actin

Question 44

g actin

Answer 44

unpolymerized globular actin proteins

Question 45

f actin

Answer 45

filamentous actin formed by polymerization of g actin

Question 46

microfilament funciton

Answer 46

structural support
cleavage furrow
structural basis of microvilli
muscle contraction
amoeboid movement
cytoplasmic streaming

Question 47

intermediated filaments

Answer 47

fibrous; more stable

provide structural strength, most diverse

Question 48

cellular respiration

Answer 48

aerobic - TCA cycle, mitochondrion

anaerobic - glycolysis, cytoplasm