Chapter 6

Question 1

basic features of all cells

Answer 1

plasma membrane, cytosol (semifluid substance), chromosomes (carry genes), ribosomes (make proteins)

Question 2

what are prokaryotic cells characterized by?

Answer 2

no nucleus, DNA in nucleoid, no membrane-bound organelles, cytoplasm bound by plasma membrane

Question 3

what are eukaryotic cells characterized by?

Answer 3

DNA in nucleus bounded by a nuclear envelope, membrane-bound organelles, cytoplasm in region between plasma membrane and nucleus

Question 4

what is the plasma membrane?

Answer 4

a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell

Question 5

how is volume affected as cell increases in size?

Answer 5

as cell increases in size, the volume grows proportionately more than its surface area

Question 6

What does plant cell have that animal cell does not?

Answer 6

have a cell wall, chloroplasts, and a large central vacuole

Question 7

what do animal cells have that plant cells do not?

Answer 7

have a centrosome

Question 8

how do ribosomes work with the DNA?

Answer 8

ribosomes use information from the DNA to make proteins

Question 9

what is the nucleus?

Answer 9

contains most of the cells genes and is usually the most conspicuous organelle

Question 10

what is the nuclear envelope?

Answer 10

encloses the nucleus, separating it from the cytoplasm

Question 11

what is the nuclear membrane?

Answer 11

a double membrane, each consisting of a lipid bilayer

Question 12

what is chromatin?

Answer 12

the dna and proteins of chromosomes together

Question 13

why does chromatin condense?

Answer 13

chromatin condenses to form discrete chromosomes as a cell prepares to divide

Question 14

what are chromosomes?

Answer 14

dna is organized into discrete units called chromosomes in the nucleus

Question 15

what are ribosomes?

Answer 15

ribosomes are complexes made of ribosomal RNA and protein and carry out protein synthesis

Question 16

where do ribosomes carry out protein synthesis?

Answer 16

cytosol (free ribosomes), outside of the endoplasmic reticulum or nuclear envelope (bound ribosomes)

Question 17

what is the function of the endomembrane system?

Answer 17

the endomembrane system regulates protein traffic and performs metabolic functions in the cell

Question 18

what does the endomembrane system consist of?

Answer 18

nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles, plasma membrane

Question 19

what does the endoplasmic reticulum do?

Answer 19

the endoplasmic reticulum accounts for more than half of the total membrane in eukaryotic cells, Smooth ER: lacks ribosomes, Rough ER: has ribosomes

Question 20

what are the functions of the smooth er?

Answer 20

synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, stores calcium ions

Question 21

functions of the rough er?

Answer 21

has bound ribosomes, which secrete glycoproteins, distributes transport vesicles, secretory proteins, and is membrane factory for the cell

Question 22

functions of the golgi apparatus?

Answer 22

modifies products of the ER, manufactures certain macromolecules, sorts and packages materials into transport vesicles

Question 23

what is a lysosome?

Answer 23

a lysosome is a membranous sac of hydrolytic enzymes that can digest macromolecules

Question 24

where do lysosomal enzymes work best?

Answer 24

in acidic environment inside the lysosome

Question 25

how is a food vacuole formed?

Answer 25

when a cell engulfs another cell by phagocytosis

Question 26

what do lysosomes do?

Answer 26

fuse with food vacuole to digest molecules, and use enzymes to recycle cell's own organelles and macromolecules in a process called autophagy

Question 27

what are vacuoles?

Answer 27

large vesicles derived from the ER and golgi apparatus

Question 28

What do central vacuoles do?

Answer 28

Only found in plants, they hold organic compounds and water

Question 29

what do contractile vacuoles do?

Answer 29

found in protists, they pump excess water out of cells

Question 30

What are mitochondria

Answer 30

Mitochondria are sites of cellular respiration

Question 31

What is cellular respiration?

Answer 31

A metabolic process that uses oxygen to generate ATP

Question 32

what are chloroplasts?

Answer 32

site of photosynthesis for plants and algae

Question 33

what are peroxisomes?

Answer 33

oxidative organelles

Question 34

what is not part of the endomembrane system?

Answer 34

mitochondria, chloroplast, peroxisomes

Question 35

What is the endosymbiont theory?

Answer 35

Suggests that an early ancestor of eukaryotes engulfed an oxygen-using nonphotosynthetic prokaryotic cell, wehre the engulfed cell and host formed a relationship and evolved into mitochondria

Question 36

Where are chloroplasts found?

Answer 36

In leaves and other green organs of plants and in algae (protists)

Question 37

chloroplast structure includes

Answer 37

thylakoids and stroma (internal fluid)

Question 38

what do peroxisomes do?

Answer 38

produce hydrogen peroxide and convert it to hydrogen and oxygen

Question 39

what is the cytoskeleton?

Answer 39

a network of fibers extending throughout the cytoplasm that organizes cell's structures and activities, and anchors organelles

Question 40

what is the cytoskeleton composed of?

Answer 40

microtubules, microfilaments, intermediate filaments

Question 41

all cells have?

Answer 41

ribosomes and chromosomes

Question 42

what is the role of the cytoskeleton?

Answer 42

to support the cell and maintain its shape, interacts with motor proteins

Question 43

what are the components of the cytoskeleton?

Answer 43

microtubules: thickest, microfilaments (actin): thinnest, intermeditate: diameters in middle range

Question 44

microtubules:

Answer 44

tubulin polymers; hollow rods 25 nm, function to shape cell, guide movement, and separate chromosomes during cell division

Question 45

microfilaments:

Answer 45

actin filaments: two intertwined strands of actin, 7 nm, tension-bearing elements, contraction, division of animal cells, also contain myosin, resist pulling forces in cell, bear tension

Question 46

intermediate filaments:

Answer 46

fibrous proteins coiled into cables, anchorage of nucleus, 8-12 nm, fix organelles in place

Question 47

what are centrosomes?

Answer 47

in animal cells, microtubules grow out of centrosome (called microtubule organizing center)

Question 48

what is cytoplasmic streaming?

Answer 48

a circular flow of cytoplasm within cells, which speeds distribution of materials within cell

Question 49

what is the cell wall?

Answer 49

an extracellular structure that distinguishes plant cells from animal cells

Question 50

who has cell walls?

Answer 50

prokaryotes, fungi, and some unicellular eukaryotes

Question 51

purpose of the cell wall

Answer 51

protect plant cell, maintain its shape, and prevents excessive uptake of water

Question 52

what are plant cell walls made of?

Answer 52

cellulose fibers embedded in other polysaccharides and protein

Question 53

What is the extracellular matrix?

Answer 53

animal cells are covered in the ECM, made up of gylcoproteins such as collagen, proteoglycans, and fibronectin

Question 54

What is the extracellular matrix?

Answer 54

animal cells are covered in the ECM, made up of gylcoproteins such as collagen, proteoglycans, and fibronectin