Module 1 - Unit 2 Flashcards
Identify the Monomer for Proteins
Amino Acids
Identify the Monomer for DNA
Prosphate
deoxyribose and
4 bases ( Adenine, Guanine, Thymine, Cytosine)
Identify the Monomer for RNA
RNA: Nucleotide containing, adenine, cytosine, guanine and uracile
What is the monomer of a lipid?
Glycerol and 3 fatty acids is the monomer of a lipid.This is also the basic structure of a lipid.
What are the monomers of sucrose?
glucose and fructose
what are the monomers of lactose?
glucose and galactose
What are the monomers of maltose?
2 glucose molecules
Describe the primary structure of a protein
• Primary:
○ Refers to the amino acid sequence or polypeptide backbone
○ Determines the 3 dimensional shape
○ 2-Dimensional
Describe the secondary structure of proteins
• Secondary:
○ 3-dimensional
○ Takes shape when the string is raised off the table and the side chains interact causing the string to fold
○ Refers to the folding of the polypeptide backbone in the protein
Describe the tertiary structure of a protein
Tertiary
○ Most proteins fold into shapes that are classified as globular and some form long fibers.
○ This structure is stabilized by mostly non-covalent forces
§ Hydrophbic interactions
§ Ionic bonds
§ Hydrogen bonds
Describe the quaternary structure of proteins
• Quarternary
○ Interaction of 2 or more polypeptide chains that associate to form a larger protein is the next conformational level
What type of bonds hold primary structured proteins together?
Peptide Bonds
What type of bonds hold secondary structured proteins together?
Hydrogen Bonds
What type of bonds hold tertiary structured proteins together?
Hydrophobic interactions
Ionic bonds
Hydrogen bonds
Briefly describe how proteins can be denatured and explain the biological impact.
Denaturation is the term used for any change in the three-dimensional structure of a protein that renders it incapable of performing its assigned function. A denatured protein cannot do its job. (Sometimes denaturation is equated with the precipitation or coagulation of a protein; our definition is a bit broader.) A wide variety of reagents and conditions, such as heat, organic compounds, pH changes, and heavy metal ions can cause protein denaturation
What are some differences between DNA and RNA?
DNA, or deoxyribonucleic acid, is like a blueprint of biological guidelines that a living organism must follow to exist and remain functional.RNA, or ribonucleic acid, helps carry out this blueprint’s guidelines. Of the two, RNA is more versatile than DNA, capable of performing numerous, diverse tasks in an organism, but DNA is more stable and holds more complex information for longer periods of time.
What are the two major stages in protein synthesis?
- Transcription
- Translation
- inititiation
- elongation
- termination
p.49-50**
What are the different types of chromosomal mutations?
○ Deletion of a gene: Gene becomes unattached to the centrometre and is lost.
○ Duplication of genes: The mutant genes are displayed twice on the same chromosome. This can prove to be advantageous as no genetic material is lost or altered and new genes are gained. The new chromosome posseses all its initial genes plus a duplicated one, which is usually harmless.
○ Inversion of genes: The order of particlular genes are reversed. The new sequence may not be viable but may also be advantageous.
○ Translocation of genes: Information from one of two homologous chromosomes breaks and binds to the other. This usually is lethal.
Name the mutations caused by alternation of the genes
○ Deletion: Loss of one nucleotide uridine in the example below leads to different sequence of amino acids.
○ Insertion: A nucleotide is inserted into a sequence. This alters the chain as in the above example and is called a frameshift alteration.
○ Inversion: This is where a particular nucleotide sequence is reversed. This may or may not be serious depending on the final amino acid that is inserted.
○ Substitution: This is where a certain nucleotide is replaced with another. An example of this type of alteration is discussed in the Case History on Sickle Cell Anemia. In this condition, the 6th amino acid on the hemoglobin beta-chain calls for glutamate but in sickle cell anemia the amino acid coded for this position calls for valine. This change has physiological consequnces as discussed in the case history. NOTE: A change in base pairs results in an amino acid change but if the new amino acid has the same chemical properties as the old one then it is unlikely to have a deleterious clinical outcome.
In what form is glucose stored in muscle?
Glycogen
Which of the following carbohydrates is a polysaccharide?
a) starch b) sucrose c) lactose d) glucose
Starch
One of the following is not consistent with the structure of a phospolipid ?
a) glycerol b) 3 free fatty acids c) 2 free fatty acids d) phosphate
3 free fatty acids ( it’s only 2 fatty acids)
- What substance is a precursor to all steroid hormones?
a) fatty acids
b) cholesterol
c) triglycerides
d) phospholipids
Cholesterol
In serum electrophoresis when a buffer solution of pH 8.6 is used, which of the following characterizes the proteins?
a) net negative charge b) net positive charge c) net zero charge d) migrate to the cathode
A net negative charge
Which of the following bases are not associated to DNA?
a) adenine b) guanine c) uracil d) cytosine
Uracil
What distinguishes 1 amino acid from another?
R-group
How many different amino acids exist?
20
The charge of an amino acid can be positive, negative or neutral. What can the nature of the charge affect?
1- Net charge of a protein
2- Effect on the ion distribution
3- Buffers
4- Structural effects
- see p. 6 for further detail)
How many of the 20 amino acids are synthesized by the human cells?
10
the remainder or essential amino acids must be obtained by our diets.
True or False
Proteins are polymers of amino acids linked together via peptide bond?
TRUE
What is the intact three dimensional structure of a protein called?
Native State
True or False?
A substitution in a single amino acid on a proton will not have a significant biological impact that can lead to to biochemical variations with presenting signs and symptoms of disease?
False
a single substitution CAN have a biological impact and repent signs and symptoms of disease
What are the different structures of proteins?
Primary
Secondary
Tertiary
Quaternary
What are the 2 common types of regular secondary structures?
x-helix ( coiled)
- hydrogen bonds are formed within the same chain
b-pleasted sheets (flat)
- hydrogen bonds are formed between different peptide
chains
Are tertiary forces weak or strong?
Weak
Most proteins in the tertiary structure fold into what shapes?
- Globular
- Fibrous
Globular proteins fulfill what types of functions?
- biocatalysts (enzymes) speed up the chemical reactions
- antibodies defend agains microorganisms
- Transport molecules efficient movement of oxygen
Are globular proteins soluble or insoluble?
Water Soluble
Are fibrous proteins soluble or insoluble?
Water insoluble
Name some fibrous proteins
Collegen (bones, connective tissue, parts of the skin, tendons…)
Keratin (hair, nails, hooves, horns…)
True or false
The lost of native state renders the protein biologically inactive?
True
What toes of agent disrupt hydrogen bonds?
- heat
- stirring solutions
- urea and quanidinium chloride
What agents disrupt hydrophobic bonds?
- change in polarity or the solvent water ( organic solvents such as acetone or ethanol)
What type of agents disrupt electrostatic interaction?
Change of the pH (hydrogen concentration)
What type of agents disrupt disulphide bridges?
agents with free sulfhydryl groups
If the net charge of a protein is 0, where will it migrate?
it won’t! no migration will occur
Where will a positively charge protein migrate?
towards the CATHODE (negative)
Where will a negatively charge protein migrate?
towards the ANODE (positive)
What is electrophoresis?
The separation of proteins on the basis of their charge in direct current electric field.
Other than the charge, what other factors will determine the actual distance that a particular protein will migrate?
- size, shape, and any interactions with the support on which the protein has been placed.
What are carbohydrates composed of?
- carbon
- hydrogen
- oxygen
ratio 1:2:1
What % of our body weight are made up of carbohydrates?
1-2%
- but they provide most of the chemical energy we utilize
What does the Benedict’s test determine?
the presence of reducing sugars.
What do all lipids have in common?
Their insolubility in water
What makes up the largest component of lipids?
Tryglicerides
True or False
As the length of the carbon chain increases in a fatty acid, so does the melting point?
TRUE
* p. 28*
_________ is a constituent of membranes and the source of steroid hormones
Cholesterol
Cell membranes are composed of 2 layers of __________ which is termed a lipid bilayer arrangement.
Phospholipid
What are the purines of DNA?
Adenine and Guanine
What are the pyrimidine bases of DNA?
Thymine and Cytosine
How many hydrogen bonds between A & T? and C&G?
2 hydrogen bonds between A=T
3 hydrogen bonds between C—G
Each pair of bases is offset by about how many degrees from the one below?
36 degrees
so a full rotation is achieved about every 10th base pair
What are the 2 steps of DNA renaturation?
1- the two complementary strands must align properly
2- The complementary hydrogen bonds between the strands must form
True or False?
Proteins always regain their biological functions after they have been denatured?
FALSE
rarely do.
but DNA does.
What are the major classes of RNA?
Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA)
Which RNA contains the information that directs the synthesis of proteins?
mRNA
Which RNA translates the genetic code into the correct amino acid sequence?
tRNA
Which RNA are integral components of the ribosomes?
rRNA
How many sets of triplets are in the “universal” genetic code?
64
* see p. 47*
True or False?
A single base change in the codon would be considered a mutation
TRUE
p.48
which organic molecule is the most abundant in cells?
Proteins ( > 15%)
Are Vitamins organic compounds synthesized by the body?
No, they must be provided by the diet
