Download 1. Name the two major divisions of metabolism, and

CHAPTER 4: CELLULAR METABOLISM
(M.C. FLATH, Ph.D.)
OBJECTIVES:
1. Name the two major divisions of metabolism, and compare and contrast them in terms of a
general descriptive sentence, additional descriptive terms, how energy is involved, whether
bonds or formed or broken, and how water is involved. Also write a chemical reaction for
each and give an example important in human metabolism.
Anabolism
SYNTHESIS
REACTIONS
Catabolism
DEGRADATION RXN'S
GENERAL
DESCRIPTION
Synthesis involves the
building of a large molecule
(polymer) from smaller
building blocks (monomer).
Degradation involves the
breakdown of polymer into
individual monomers.
DESCRIPTIVE TERMS
building
constructive
anabolic
breakdown
digestive
decomposition
catabolic
BOND FORMATION OR
BREAKING?
Bonds are formed.
Bonds are broken.
IS ENERGY REQUIRED
OR RELEASED?
NAME THAT TERM.
Energy is required to form
the bond.
Endergonic
Energy is released when the
bond is broken.
Exergonic
HOW IS WATER
INVOLVED?
NAME THAT TERM.
Water is released when he
bond is formed.
Dehydration
Water is required to break
the bond.
Hydrolysis
EXAMPLE
Building a protein from
individual amino acids;
Building a triglyceride from
glycerol and 3 fatty acids, etc
Breaking a protein into
individual amino acids;
Breaking starch down into
monosaccharides, etc.
2.
Define the term enzyme and discuss the general characteristics of an enzyme. Be
sure to discuss the mechanism by which most enzymes function (i.e. how do they
react with their substrate and cofactor/coenzyme), and explain how most enzymes
are named, giving examples when applicable.
An enzyme is a biological protein catalyst that increases the rate of a chemical reaction without being
consumed by the reaction.
An enzyme has a very specific shape and fits together with its substrate like a lock and key through the
enzyme’s active site.
The enzyme and substrate come together to form the enzyme - substrate complex.
Then the reaction occurs and the end-products are released and the unaltered enzyme is released
and can be used over and over again.
The enzyme’s active site may not always be exposed, and a substance called a coenzyme
or cofactor may be required to activate the enzyme. B vitamins are examples of coenzymes and minerals
are example of cofactors.
Enzymes are named for the substrate they act upon. The root of the enzyme name
typically comes from the substrate and the suffix -ASE is added at the end.
For example, the enzyme lactase acts upon the substrate lactose.
And the enzyme lipase acts upon a substrate lipid or fat.
In extreme conditions, enzymes can be denatured which results in loss of function.
Enzymes typically occur in a particular sequence within metabolic pathways.
DIAGRAM: See your notes from class!!!!
3.
Define the term substrate.
A substrate is acted upon by an enzyme in a metabolic reaction. For example, the enzyme
lactase acts upon the substrate lactose.
4.
Explain why most enzymes need a vitamin (coenzyme) or mineral (cofactor) to function,
and name the site where this coenzyme or cofactor bind the enzyme.
The enzyme’s active site may not always be exposed, and a substance called a coenzyme or
cofactor may be required to activate the enzyme. B vitamins are examples of coenzymes and
minerals are example of cofactors
5.
Name the three components of ATP and describe its function in living cells.
Ribose
adenine
3 phosphates
6.
Write a simple chemical equation showing the reversible reaction of ATP/ADP.
ATP ---- ADP + Pi
8.
Compare the two major steps in cellular respiration in terms of:
a.
b.
c.
d.
e.
name
their location in the cell;
whether oxygen is required;
initial compounds and end-products;
number of ATP molecules produced.
And draw an overview diagram of CR including this information
ANAEROBIC
AEROBIC
Name of
step(s)
GLYCOLYSIS
LOCATION
in cell
Is Oxygen
Required?
Starting
Product(s)
CYTOPLASM
KREB’S CYCLE (CITRIC ACID
CYLE) AND ELECTRON
TRANSPORT CHAIN
MITOCHONDRION
NO
YES
GLUCOSE (6-C)
2 PYRUVIC ACIDS
2 ATP
EndProducts
2 PYRUVIC ACIDS
36 ATP
WATER
CARBONDIOXIDE
CELLULAR RESPIRATION
ANAEROBIC RESPIRATION
CYTOPLASM
GLYCOLYSIS
AEROBIC RESPIRATIION
MITOCHONDRIA
(KC, ETC)
GLUCOSE (6C )→→→→→→→ PYRUVATE (2X3C) →→→→→→CO2, H2O. 36 ATP
+ 2ATP
fermentation
Lactic acid
←←←←←←←←←←
10.
Describe the fate of pyruvic acid in the absence of oxygen.
It is fermented to lactic acid in animal cells.
11.
Distinguish between aerobic and anaerobic respiration in terms of energy production.
anaerobic respiration
aerobic respiration
Energy released
2 ATP
36 ATP
12.
Name the greatest reserve fuel in the body.
FAT
13.
Name the specific substance that is required for each and every step of metabolism.
An ENZYME is required for each and every step of metabolism.
14.
Explain why an enzyme that catalyzes a step in glycolysis would not be required for a
step in Beta-oxidation (i.e. fat metabolism)
Because enzymes are specific for their substrates.
15. Construct a molecule of DNA. Be sure to label parts fully (if using abbreviations, make
sure to provide a key).
16.
Describe the function of deoxyribonucleic acid (DNA) and RNA.
DNA
RNA
Directs protein synthesis
Assists DNA in protein synthesis
17.
Explain why protein synthesis is so ultimately important in living things.
Proteins have many functions in human metabolism including enzymes which regulate each
and every metabolic reaction.
18.
Define the term gene, and give the approximate number of genes that compose the human
genome.
A gene is the portion of a DNS molecule that codes for one particular protein.
There are approximately 34000 genes in the human genome.
19.
Distinguish ribonucleic acid (RNA) from DNA, in terms of structure, where each is
located in a human cell, and the function of each.
DNA
RNA
STRUCTURE
1. SUGAR = deoxyribose
1. ribose
2. BASES = adenine (A); 2. adenine (A); uracil (U));
thymine (T); cytosine (C); cytosine (C); and guanine (G)
and guanine (G)
LOCATION IN CELL
FUNCTION
3. DOUBLE OR SINGLE 3. SS
STRANDED? DS
nucleus
Made in nucleus, but
functions at ribosomes in
cytoplasm or in rough
endoplasmic reticulum
Directs protein synthesis
Assist in protein synthesis
20.
Name the two major steps of protein synthesis, and compare and contrast them in terms
of where they occur in the cell, start products, molecules (including enzyme names) involved in
each step, and end products. PROTEIN SYNTHESIS SUMMARY TABLE (outline page 15)
NAME OF STEP
TRANSCRIPTION
TRANSLATION
Nucleus
at a ribosome either that is
LOCATION IN CELL
either free in the cytoplasm or
on rough endoplasmic
reticulum
START PRODUCT
DNA (GENE)
Messenger RNA
DNA: unwinds & unzips
mRNA carries the protein code
MOLECULES INVOLVED
to the ribosome;
AND HOW?
RNA Polymerase (an enzyme)
Ribosome if the protein
positions the complementary
synthesizing machinery;
RNA nucleotides along the
Transfer RNA (tRNA) brings
DNA template and zips up their the appropriate amino acid to
backbone.
the ribosome to be incorporated
into the protein..
A strand of mRNA
A protein
END PRODUCT
21.
Describe the role of messenger RNA (mRNA), transfer RNA (tRNA) and ribosomal
RNA (rRNA) in protein synthesis.
mRNA
tRNA
rRNA
Carries the code for the Brings the appropriate amino Composes the ribosome along
protein to be made from the acid to the ribosome to be with proteins.
nucleus to the ribosome
incorporated into the protein
22.
Explain how amino acids are joined to form a protein. Through a peptide bond.
23.
Given the following DNA sequence (gene) and the mRNA codon chart that I distributed
in class, determine the peptide (protein) which will result.
DNA Base Sequence
Messenger RNA Base Amino Acid Sequence tRNA
anticodon
(GENE)
Sequence (mRNA)
(PROTEIN)
sequence
T
A
U
MET
A
U
A
C
G
C
T
A
U
ILE
A
U
A
A
U
A
C
G
T
C
C
G
T
A
A
A
T
T
G
C
A
G
G
C
A
U
U
U
A
A
ALA
GLY
ILE
STOP
C
G
T
C
C
G
U
A
A
A
U
U
24.
Describe the steps involved in DNA replication, name the location in the cell where DNA
replicates, name the enzyme required for DNA replication, and explain the significance
of the process.
DNA replication steps TRANSCRIPTION
TRANSLATION
Location in cell
NUCLEUS
Enzyme that assists
Significance
RNA POLYMERASE
N/A
Results in mRNA that now
carries code for protein to be Results in a protein.
made to ribosome.
AT RIBOSOME EITHER
CYTOPLASM OR ON RER
IN
25.
Describe what is meant by "semi-conservative" replication.
The two copies of DNA have been synthesized and each has one old strand and one new strand
of DNA.
26.
Define the term mutation, and explain its significance in protein synthesis.
A mutation is an error in a gene (DNA sequence).
Results of mutations include an enzyme that is not made at all, a protein with an altered
structure/function, or a protein to be made in excess.