Eukaryotes

Question 1

eukaryotic vs prokaryotic cells

Answer 1

eukaryotic are much more complex - compartmentalized with internal membranes - have organelles

Question 2

organelles

Answer 2

bodies inside eukaryotic cells surrounded by their own membranes, each is specialized for a certain function

Question 3

advantages of being compartmentalized

Answer 3

1) ph, enzyme, and substrate levels can be kept at optimal levels for each specific process happening inside the cell (processes cannot intervene with each other)
2) free radicals, peroxide, and other strong oxidizing agents cannot intoxicate/damage other parts of the cell (free radicals in the mitochondria)
3) organelles can be moved around the cell (mitochondria for example)

Question 4

parts of an eukaryotic cell

Answer 4

• nucleus
• rough endoplasmic reticulum
• smooth endoplasmic reticulum
• Golgi apparatus
• vesicles
• ribosomes
• mitochondrion
• chloroplast (only in plant)
• microtubules
• vacuole (only in plant)
• cilia & flagella
• plasma membrane
• cell wall (only in plant)
• cytoskeletal proteins

Question 5

nucleus

Answer 5

• largest and heaviest organelle in animal cell
• controls processes inside the cell by controlling the process of gene expression (protein synthesis)
• surrounded by a nuclear membrane (phospholipid bilayer) with nuclear pores
• contains nucleoplasm (=nucleolus + chromatin)
• nucleolus - densely packed DNA + RNA + proteins
• chromatin - 46 uncoiled DNA molecules associated with histone (chromosome formation) - more densely packed at the edge of the nucleus

Question 6

rER

Answer 6

• organelle with a single membrane
• cisternae - flattened membrane sacs that the rER is made of
• ribosomes are attached to the cisternae (bound ribosomes)

Question 7

Golgi apparatus

Answer 7

• made our of cisternae shorter and more curved than those in ER
• have no ribosomes
• final modification/refinement of proteins created in ER - packed into vesicles and secreted (many vesicles next to GA)

Question 8

vesicles

Answer 8

• organelles with a single membrane with fluid inside
• can be formed as a result of budding of GA or after endocytosis
• contain proteins (dark in EM picture)
• lysosomes (lysozyme) and peroxisomes (catalase)

Question 9

lysosome

Answer 9

contains lysozyme which is used in internal digestion of damaged cell particles/organelles - only animal cells have them

Question 10

ribosomes

Answer 10

• nor organelles (no membrane)
• composed of rRNA and proteins (formed in the nucleus)
• big and small subunit
• 70S and 80S type - Svedberg is the unit indicating how fast something sediments when centrifuged

Question 11

proteins synthesized on free vs on bound ribosomes

Answer 11

on free - stay inside the cell
on bound - get transported outside of the cell

Question 12

role of the smooth endoplasmic reticulum

Answer 12

production of carbohydrates and lipids

Question 13

how do proteins get refined/modified in the rER?

Answer 13

their quarternary structure gets built (conjugated proteins get their prosthetic groups, etc)

Question 14

how are hormone-producing cells (hormonal glands, pancreas, salivary and stomach glands…) different from other cells (physically)?

Answer 14

they have an extensive rER for all that protein production (protein usually seen on the photo of the cells)

Question 15

plastid and centrioles

Answer 15

plastid - a family of double-membraned organelles - like chloroplast (green) also exist red, orange, yellow… - only plants have them!!
centrioles - elongated cylindrical structures - in animal cells only!!

Question 16

mitochondrion

Answer 16

• site of cell respiration
• surrounded by a double membrane
• ribosomes, matrix, inner membrane, outer membrane, intermembrane space, starch grains, cristae, mDNA

Question 17

chloroplast

Answer 17

• surrounded by a double membrane
• thylakoid membrane containing chlorophyll and other pigments
• site of photosynthesis
• stroma, outer membrane, inner memmbrane, granum, thylakoids

Question 18

vacuole

Answer 18

• a big vesicle
• largest organelle in plant cells
• stores water and other juices with dissolved compounds (like nicotine in tobacco plants)
• vesicles in animal cells are smaller and non-permanent

Question 19

cilia and flagella

Answer 19

• project from the cell surface
• only in animal cells!! (cilia)
• cilia have the same function as pilli in prokaryotic cells (attachment)
• used for locomotion (movement)

Question 20

plasma membrane

Answer 20

• composed of phospholipids and proteins
• controls the transport in and out of the cell (endocytosis and exocytosis)

Question 21

chitin

Answer 21

found in cell walls of fungi cells - plant cell walls are made out of cellulose

Question 22

number of membranes
0
1
2

Answer 22

• 80S ribosomes, microtubules, microfilaments
• rER, sER, Golgi apparatus, lysosomes, vesicles, vacuoles
• nucleus, mitochondria, chloroplasts