Lecture 5-7

Question 1

What is ATP

Answer 1

Adenosine Triphosphate

Question 2

Energy source for cells

Answer 2

ATP

Question 3

Why is carbon fundamental in organic molecules in cells?

Answer 3

Carbon based molecules are a stable energy storage source

Question 4

Why is ATP such a good energy source?

Answer 4

Contains 3 phosphate bonds; bonds contain high potential energy

Question 5

Phototroph (def.)

Answer 5

Gaines energy from the sun

Question 6

Chemotroph (def.)

Answer 6

Gains energy from chemical compounds

Question 7

Autotroph (def.)

Answer 7

Gain carbon from inorganic sources

Question 8

Heterotroph (def.)

Answer 8

Gain carbon from organic compounds

Question 9

Catabolism (def.)

Answer 9

Breaking down of molecules —> production of ATP

Question 10

Anabolism

Answer 10

Building of molecules —> input of ATP required

Question 11

Metabolism (def.)

Answer 11

The building and breaking down of carbon sources to harness or release energy

Question 12

Chemical reactions in cells are catalyzed by proteins called ____

Answer 12

Enzymes

Question 13

What is a transition state

Answer 13

As a new compound forms, it is temporarily unstable and has a lot of free energy

Question 14

Explain this model:
Substrate+Enzyme –>ES–>EP–>Enzyme+Product

Answer 14

Substrate forms complex with enzyme, enzyme helps speed up reaction, product is formed with still part of the complex, complex dissociated and releases enzyme and product

Question 15

2 types of substrate + active site interactions

Answer 15

1. Weak non-covalent interactions
2. Transient covalent bonds

Question 16

Why are enzymes so important in chemical reactions?

Answer 16

Speed up process, stabilize transition state and decrease energy input needed

Question 17

Active site formation

Answer 17

Active site amino acids are spaced out on protein chain, protein folds to form enzyme and amino acids come together to form active site

Question 18

Enzyme specificity (def.)

Answer 18

Enzyme active site is highly specific for substrate and reaction catalyzed

Question 19

2 ways enzyme activity can be influenced

Answer 19

1. Inhibitors
2. Activators

Question 20

Inhibitor (def.)

Answer 20

Decrease activity of enzyme

Question 21

2 types of inhibitors

Answer 21

Reversible and non-reversible

Question 22

What kind of bonds do inhibitors form?

Answer 22

Reversible: form weak bonds
Non-reversible: form covalent bonds

Question 23

Type 1 enzyme inhibitors process

Answer 23

Inhibitor has similar shape as substrate, binds to active site, blocking substrate from binding

Question 24

Type 2 enzyme inhibitor process

Answer 24

Has a different shape as substrate (does not have to compete for active site), binds to inhibitor site and changes shape/function of enzyme

Question 25

Allosteric enzyme (def.)

Answer 25

Enzymes that have inhibitor sites (can be reversible or non-reversible)

Question 26

mRNA carry the instructions to make _____

Answer 26

Proteins

Question 27

DNA (def.)

Answer 27

Information molecule encoding heritable information used by cells to make molecules needed to survive; double stranded helix

Question 28

Job of RNA

Answer 28

Decode and sequence amino acids in a polypeptide chain that will fold to make a functional protein molecule

Question 29

Base pairs for DNA

Answer 29

A — T G — C

Question 30

Base pairs for RNA

Answer 30

A — U G — C

Question 31

Transcription

Answer 31

Makes a single stranded copy of RNA (mRNA) of a sequence of DNA nucleotides

Question 32

Translation

Answer 32

Takes instructions encoded in mRNA and translates them into a new language that can make a polypeptide chain

Question 33

Ribosome (def.)

Answer 33

Structures made of RNA and protein, not membrane bound organelles, bind with mRNA and accept tRNA with amino acids, provides a structure for translation to take place, arranges order of charged tRNA to match mRNA

Question 34

Charged tRNA (def.)

Answer 34

tRNA with 1 amino acid attached

Question 35

tRNA functions

Answer 35

1. Carries amino acid 2. Associates with mRNA 3. Interacts with ribosomes

Question 36

What is a CCA nucleotide?

Answer 36

An attachment site for amino acids, on the 3’ end on an mRNA

Question 37

Genetic Code (def.)

Answer 37

Related genes in DNA to mRNA and relates mRNA to amino acids (proteins) using tRNA

Question 38

How is mRNA read?

Answer 38

Read in 3 base segments called codons

Question 39

Start Codon

Answer 39

AUG – methionine (Acts as initiation signal for translation)

Question 40

Stop Codons (3)

Answer 40

UAA, UAG, UGA (Direct ribosomes to end translation)

Question 41

What is wobble?

Answer 41

Variation of last position of tRNA with mRNA after first 2 positions are paired

Question 42

tRNA anticodon with the mRNA codon proceeds from where?

Answer 42

5’ end of the codon

Question 43

Steps of translation

Answer 43

1. Initiation 2. Elongation 3. Termination

Question 44

What is contained in the initiation complex?

Answer 44

Small sub unit of mRNA, tRNA, methionine, initiation factors

Question 45

Steps in Initiation (Translate)

Answer 45

1. Moves along mRNA to find AUG 2. Initiation factors release, charged tRNA ready to join ribosome 3. Bond connecting Met to tRNA is transferred to amino group of next amino acid in line 4. Ribosome shifts 1 codon to right, moving now uncharged tRNA to E site and getting ejected

Question 46

Steps of Termination (translation)

Answer 46

1. Stop codon is encountered 2. Protein release factor binds to A site of ribosome, bond connecting polypeptide to tRNA breaks 3. Breaking of the bond creates the carboxyl terminus and completes chain

Question 47

Post translation events

Answer 47

1. Polypeptide chain undergoes folding into 3D shape 2. Polypeptide chain may be modified by trimming or addition/removal of chemical groups 3. Polypeptide may be relocated within cell or secreted