Exam 1 Review- Lecture 3

Question 1

What is the rough/ granular RER?

Answer 1

Ribosomes bound to cytosolic surface and has a flattened sac appearance

Synthesizes and packages proteins in to transport vesicles for delivery to Golgi apparatus

Folds proteins into secondary and tertiary structures

Question 2

What is the smooth/ agranular SER?

Answer 2

No ribosomal particles on its surface abs has a branched, tubular structure

Site of lipid synthesis (phospholipid, steroids and cholesterol)

Detoxified hydrophobic molecules

Stores and releases calcium for muscle contraction

Question 3

What is the Golgi apparatus (GA)?

Answer 3

Serious of closely flattened membranous sacs that are slightly curved

Question 4

What are the functions of the Golgi apparatus (GA)?

Answer 4

• processes raw material to finished products (modifies)- adds or removes carbs from or to proteins
• sorts and directs finished product to final destination- packages enzymes within lysosomes for use in cytoplasm and renews or modified plasma membrane
• packages secretory vesicles to be secreted from cell

Question 5

What is the genetic language?

Answer 5

Contains 4 letters, corresponding to bases: A C T G

Genetic words are 3 base sequences that specify particular amino acids

3 letters long = triplet code

Sequence of triplet code along a gene in a single strand of DNA specifies sequence of amino acids in a polypeptide chain

Question 6

What are the steps of translation (mRNA to protein)?

Answer 6

1) after leaving nucleus, mRNA bonds to ribosomal subunit of cytoplasm
2) each mRNA codon translates to 1 amino acid
3) amino acids are delivered by tRNA
4) a tRNA anticodon bonds to a complementary mRNA codon
5) enzymes join amino acid with peptide bonds
6) at stop codon, components separate

Question 7

What is transfer RNA (tRNA)?

Answer 7

Smallest of the major classes of RNA

Single chain of tRNA loops back upon itself, forming a a clover like leaf shape w/ 3 loops

Combines w/ a specific amino acid & a codon on mRNA specific for that amino acid

tRNA is linked b/n an amnio acid & mRNA codon for that amino acid

tRNA molecule is covalently linked to a specific amino acid by aminoacyl-tRNA synthetase

A 3-nucleotide sequence at 1 end of the loops of tRNA (anticodon) base pairs w/ a complementary codon in mRNA

Question 8

What is an effective barrier and why?

Answer 8

Plasma membrane

Why?

• let’s nutrients in
• products and waste must come out

Question 9

What is permeability?

Answer 9

Waste with dissolved materials can cross the membrane

Question 10

What is impermeable?

Answer 10

Nothing can pass through membrane

Question 11

What is freely permeable?

Answer 11

Anything can pass through membrane

Question 12

What is Selectively permeable and what does the membrane restrict/ permits substances based on?

Answer 12

Certain things can pass through membrane while others cannot

Depends on:

• charge
• molecular shape
• lipid solubility
• size

Question 13

What are 5 factors affecting diffusion?

Answer 13

1) temperature
2) ion and molecule size
3) concentration gradient
4) distance particles have to move
5) electrical forces

Question 14

Explain how temperature affects diffusion

Answer 14

Higher temp = greater speed of molecular movement —-> faster diffusion

Question 15

Explain how ion and molecule size affects diffusion

Answer 15

Smaller ion and molecule size —-> faster diffusion

Question 16

Explain how concentration gradient affects diffusion

Answer 16

Steeper the gradient —-> faster diffusion

Ex: when cells become more active, they use O2 —> decreasing intracellular O2 concentration —> increases concentration gradient of O2 b/n inside of cell (low) and interstitial fluid outside (high)
Rate of O2 diffusion into cells increase

Question 17

Explain how distance particle has to move affects diffusion

Answer 17

Shorter the distance = more quickly concentration gradient are eliminated —-> faster diffusion

Question 18

Explain how electrical forces affects diffusion

Answer 18

Opposites attract

Like charges repel

Ex: cytoplasmic (inner) surface of plasma membrane has a net negative charge relative to extracellular (outer) surface
Negative charge attracts positive ions from ECF (Na+) into cell, while repelling entry of negative ions

Question 19

What is tonicity and the 3 types?

Answer 19

Describes how a solution affects shape of a cell (alters internal water volume via osmosis)

Question 20

What is isotonic solution?

Answer 20

Iso- same
Tonic- pressure

2 solutions have equal solute (osmotic) concentrations

No osmotic flow

No change in cell size or shape

Question 21

What is hypotonic solution?

Answer 21

Hypo- below
Tonic- tension

Lower solute (osmotic) concentration than cell

Cell take on water, swells, and ruptures (hemolysis)

Question 22

What is hypertonic solution?

Answer 22

Hyper- above
Tonic- pressure

Higher solute (osmotic) concentration than cell

Cell loses water by osmosis and shrinks (crenation)