cells part 2

Question 1

ribosomes

Answer 1

-sites of protein synthesis
-similar structure in prokaryotes and eukaryotes
-consist of two subunits: each with ribosomal RNA bound to protein molecules

Question 2

nucleus

Answer 2

-usually the largest organelle
-contains most of the DNA
-site of DNA replication
-gene transcription is turned on/off
-assembly of ribosomes

Question 3

chromatin

Answer 3

DNA combines with proteins

Question 4

chromosomes

Answer 4

chromatin in long, thin threads

Question 5

nuclear envelope

Answer 5

a double membrane

Question 6

nuclear pores

Answer 6

regulates what goes in and out

Question 7

endomembrane system

Answer 7

interconnected system of membrane-enclosed compartments; including the nucleus, rough and smooth endoplasmic reticulum, Golgi apparatus, and vesicles

Question 8

vesicles

Answer 8

tiny membrane shuttle substances between the various components

Question 9

endoplasmic reticulum

Answer 9

network membranes in the cytoplasm; large surface area

Question 10

rough endoplasmic reticulum

Answer 10

ribosomes are attached; newly made proteins enter the RER lumen and are modified, folded, and transported to other regions in vesicles that pinch off the RER

Question 11

smooth endplasmic reticulum

Answer 11

-no ribosomes
-site for detoxifying
-site of glycogen degradation in animal cells
-synthesis of lipids and steroids
-stores calcium ions

Question 12

golgi apparatus

Answer 12

flattened sacs (cristenae) and small vesicles; receives proteins from RER; modifies, concentrates, packages, and sorts proteins; in plant cells, polysaccharides for cell walls are synthesized

Question 13

mitochondria

Answer 13

the powerhouse of the cell; energy in fuel molecules such as glucose is transformed into the bonds of energy-rich ATP (cellular respiration); cells that require a lot of energy have many mitochondria; they can reproduce and divide independently of the central nucleus; mitochondria has two membranes

Question 14

inner membrane of mitochondria

Answer 14

folds inward to form cristae—creates a large surface area for embedded proteins involved in cellular respiration; mitochondria matrix contains DNA and ribosomes to make the proteins needed for cellular respiration

Question 15

outer membrane of mitochondria

Answer 15

protects the inside

Question 16

plastids

Answer 16

only in plants and some protists; site of photosynthesis where all sugars come from

Question 17

chloroplasts

Answer 17

site of photosynthesis; have double membrane; can divide independently of the nucleus

Question 18

thylakoids

Answer 18

formed by the inner membrane; contain chlorophyll and other pigments that harvest light energy

Question 19

chromoplasts

Answer 19

contain red, yellow, and orange pigments; give color to flowers; chromo means color

Question 20

leucoplasts

Answer 20

stores starches and fats; leuco means white

Question 21

peroxisomes

Answer 21

collect and break down toxic byproducts of metabolism, using special enzymes

Question 22

gloxysomes

Answer 22

only in plants—lipids are converted to carbohydrates for growth

Question 23

vacuoles

Answer 23

-in plants and protists
-nothing but liquid
-give fruits and flowers color
-provides structure for plant cells
-store pink and blue pigments
-the color attracts pollinators

Question 24

phagocytosis

Answer 24

phogo means eating; food molecules enter the cell; a phagosome is formed

Question 25

lysosomes

Answer 25

contain digestive enzymes that hydrolyze macromolecules into monomers

Question 26

primary lysosomes

Answer 26

originate from the golgi apparatus

Question 27

secondary lysosomes

Answer 27

phagosomes fuse with primary lysosomes; enzymes hydrolyze the food molecules

Question 28

exocytosis

Answer 28

wastes are ejected

Question 29

importance of compartmentalization in eukaryotic cells

Answer 29

-organelles carry out particular biochemical functions that support the cells’ overall function
-separating biochemical reactions increases cell efficiency
-one compartment might break down proteins, another compartment might build them

Question 30

animal subcellular structures

Answer 30

mitochondria: powerhouse
nucleus: site of cellular DNA-associated proteins comprised of chromatin
cytoskeleton: support, shape movement
centrioles: nuclear division
cell membrane: regulates traffic
RER: protein synthesis

Question 31

plant subcellular structures

Answer 31

cell wall: support
SER: molecules are metabolized
ribosomes: manufacture proteins
peroxisome: break toxic peroxides
chloroplast: energy of the sun to make sugar
Golgi apparatus: process and package proteins

Question 32

trace the path of a molecule as it moves between organelles in a eukaryotic cell

Answer 32

1) synthesis of proteins on ribosomes which translates mRNA into polypeptides entering RER
2) protein is modified in RER (folding addition of sugars). protein-containing vesicles transfer substance from ER to Golgi apparatus
3) Golgi apparatus sends vesicles to the correct destination
4) once at the correct destination proteins perform their specific function