3.2-3.3 Eukaryotic Cells

Question 1

what is an eukaryotic cell

Answer 1

presence of nucleus + organelles surrounded by mebrane

animals, plants,fungi, protists

Question 2

plasma (cell) membrane

Answer 2

-c: phospholipid bilayer embedded w protein molecules
-f: living boundary that separates living contents of cell from surrounding environment
regulates entrance/exit of molecules into and out of cell

Question 3

cytoplasm

Answer 3

c: water, salts, dissolved organic molecules
f: semi fluid medium inside of cell

Question 4

cell walls

Answer 4

PLANT CELLS ONLY
c: primary cell wall composed of cellulose that forms firbils that lie right angle to each other for added strength
secondary cell wall composed of lignin, stronger than primary cell wall
fungi cell wall composed of chitin and cellulose
algae (protista fam) cell walls composed of chitin

Question 5

define organelle

Answer 5

originally only referred to membraneous structures, now means any well defined subcellular structure that performs a particular function

Question 6

nucleus

Answer 6

c: nuclear envelope, nucleoplasm, chromatin, nucleoli
f: stores genetic information, synthesis of DNA and RNA

Question 7

what is chromatin (chromosomes, nucleoplasm)

Answer 7

• consists of DNA associated w proteins
• in cells lifetime, chromatin present but when cell ready to undergo cell division, it will undergo coiling and become chromosomes (highly condensed structures) immersed in semifluid medium NUCLEOPLASM
• humans have 46 chromosomes

Question 8

what does a difference in pH between the necleoplasm and cytoplasm suggest

Answer 8

nucleoplasm has a diff composition

Question 9

nucleolus (nucleoli plu)

Answer 9

c: concentrated area of chromatin, RNA, proteins
f: forms rRNA (ribosomal RNA) that joins w proteins to form subunits of ribosomes

Question 10

what is a nuclear envelope

Answer 10

double membrane that separates nucleus from cytoplasm, which is continuous to endoplasmic reticulum

Question 11

what are nuclear pores

Answer 11

pores of 100nm that permit the directional transport of proteins and ribosomal subunits
-can control events within nucleus or entire cell

Question 12

what happens in the nucleus during cell division

Answer 12

• nuclear envelope completely disappears
• contents of nucleus completely mixed w cytoplasm
• following cell division, nuclear envelope re-forms around chromosomes and other contents of nucleus transported into nucleus

Question 13

ribosomes

Answer 13

c: protein and RNA in two subunits “large” and “small”
f: protein synthesis, found in cytoplasm, or attached to ER

Question 14

what are the components of the endomembrane system

Answer 14

nuclear envelope, endoplasmic reticulum, golgi apparatus, vesicles

Question 15

vesicles

Answer 15

c: membranous sacs of various sizes
f: storage of substances

Question 16

endoplasmic reticulum

Answer 16

c: complicated system of membranous channels and sacs, continuous w outer membrane of nuclear envelope
f: synthesis,modification of proteins and other substances, distribution by vesicle formation

Question 17

rough ER

Answer 17

c: network of folded membranes studded w ribosomes on side that faces cytoplasm
f: as proteins are synthesized on these ribosomes that pass into ER, where processing and modification begin (proteins synthesized here either exocytosis or endocytosis)
-folding, modification, processing, transport of proteins
EX) cystic fibrosis: mutated plasma membrane channel protein remains in ER bc folded incorrectly, cell not in correct place unable to regulate transport of chlroide ions = various symptoms of diseases

Question 18

smooth ER

Answer 18

c: network of folded membranes having no ribosomes continuous w rough ER
f: -synthesizes phospholipids found in cell membranes
- forms vesicles which products are transports to Golgi apparatus
- in testes produces testosterone
- in liver detoxifies drugs
- in muscle cells stores calcium ions

Question 19

Golgi apparatus (body)

Answer 19

c: stack of 3-20 slightly curved membraneous sacs
f: collects, sorts, packages, distributes materials like proteins and lipids
-formation of lysosomes
-one side of stack (inner face) directed towards ER
-other side (outer face) directed towards plasma membrane
vesicles can frequently be seen at the edges of sacs

Question 20

what is the process of secretion

Answer 20

• golgi body receives proteins and lipid filled vesivles from ER
• molecules move through golgi from inner face to outer face, during passage, proteins, lipids, modified before repackaged into secretory vesicles
• secretory vesicles proceed to plasma membrane where secreted

Question 21

lysosomes

Answer 21

ANIMAL CELL

c: membrane vesicle containing hydrolytic digestive enzymes
f: intracellular digestion; macromolecules brought into cell by vesicle formation at plasma membrane, when lysosome fuses w vesicle, its contents are digested by lysosomal enzymes into simpler subunits that enter cytoplasm

Question 22

vacuole

Answer 22

c: large membranous sacs, larger than vesicle, plants have larger vacuole filled w watery fluid that provides additional support to cell
f: stores substances, plant vacuoles store water, sugars, salts, pigments, toxic molecules
(pigments for colour, toxic molecules that protect plant from herbivorous animals)

Question 23

peroxisomes

Answer 23

c: membranous vesicle containing specific enzymes that are synthesized by cytoplasmic ribosomes and transported to peroxisome by carrier proteins
f: metabolic tasks
-cells that synthesis and break down fats
liver it break down fats and produce bile salts from chloestrol
-plant cells: oxidize fatty scids into molecules that can be converted to sugars needed by the growing plant
-leaves: carry rxn opp. to photosynthesis, use O2, releases CO2
RH2 + O2 -> R + H2O2 contain enzyme that action result in hydrogen peroxide

Question 24

which organelles specialize in converting energy to a form cells can use

Answer 24

chloroplasts and mitochondria

Question 25

chloroplasts

Answer 25

PRIMARILY PLANT CELLS

c: membranous grana bounded by two membranes in a fluid filled space called the stroma which contains a single ciruclar DNA molecule as well as a ribosome
- contains own genetic matieral makes own proteins
f: photosynthesis (solar energy +CO2 +H2O -> CARB +O2)
- membrane system in stroma organized into interconnected flattened sacs (thylakoids) stacked up to structures in granna (can be hundreds)
- chlorophyll (located in thylakoid membrane of grana) capture solar energy needed to enable chloroplasts to produce carbohydrates just read pg 76

Question 26

mitochondria

Answer 26

c: inner membrane (cristae) bounded an outer membrane
f: cellular respiration

Question 27

what is the matrix and cristae

Answer 27

matrix: inner fluid filled space in mitochondria. contains ribosomes and enzymes that break down carbohydrate products and release energy used for ATP production
cristae: inner membrane of mitochondrion folded inwards on itself, provides more surface area to accomodate protein complexes and other participants that produce ATP

Question 28

cytoskeleton

Answer 28

protein components of cytoskeleton interconnect and extend from nucleus to plasma membrane

c: contains actin filaments, intermediate filaments, and microtubules which maintain cell shape and allow cell and organelles to move
f: shape of cell and movements of part

Question 29

what are actin filaments

Answer 29

long, extremely thin, flexible fibres that occur in bundles of meshlike networks

• each contain 2 chains of globular actin monomers twisted about one another in a helical manner
• complex web under plasma membrane anchored by special proteins
• in microvilli that project from intestinal cells

Question 30

what are motor molecules

Answer 30

proteins that can attach, detach, and reattach farther along the actin filament
-to produce movements, actin filaments ineract w motor molecules

Question 31

what are intermediate filaments

Answer 31

• perform structural role in cell
• rope like assembly of fibrous polypeptides
• inermediate size between actin filaments and microtubules

Question 32

what are microtubules

Answer 32

small, hollow cylinders 25nm long, 0.2 - 25 microm long

• made up of globular protein tubulin (2 types: alpha and beta)
• 13 rows of tubulin dimers surrounding an empty core

Question 33

what is a centrosome

Answer 33

main microtubule organizing centre lies near nucleus

• microtubules radiate from centrosome maintaining shape of cell and acting as tracks which organelles can move
• before a cell divides, microtubules disassemble and reassemble into spindle that attaches to chromosome and ensures that they are distributed evenly, at the end of cell division spindle disassembles and microtubules reassemble to form former array

Question 34

centriole

Answer 34

c: short cylinders of microtubules with 9 sets of 3 + 0 pattern of microtubules,
f: formation of basal bodies, replicate so that members of each pair are right angle to one another. then, each pair becomes part of separate centrosome

Question 35

cilia and flagella

Answer 35

c: 9 + 2 pattern of microtubules
f: movement of cells