B1.2 and A1.2 Proteins / Nucleic Acids Flashcards
What is the relationship between amino acid sequence and the diversity in form and function of proteins? How are protein molecules affected by their chemical and physical environments?
Which of the following is NOT a function of proteins in biological systems?
- Catalysis of reactions
- Transport of oxygen
- Genetic information storage
- Structural support
Genetic information storage
What type of bond forms between amino acids during protein synthesis?
peptide bond
Which level of protein structure is characterized by a-helices and b-pleated sheets?
Secondary Structure
The primary structure of a protein refers to:
The sequence of amino acids
Which type of interaction stabilizes the tertiary structure of a protein?
Disulfide bridges
What type of bond forms between the phosphate of one nucleotide and the sugar of the next nucleotide in a DNA strand?
Phosphodiester bonds
Two strands of DNA are held together by _________.
Hydrogen bonds between nitrogenous bases
Adenine and Guanine are _________.
Purines
DNA (Deoxyribonucleic acid) is the ________ ________ for all living organisms.
genetic material
DNA is found in chromosomes and contains the genetic information for the _____ and development of individual cells and organisms.
growth
How does the structure of nucleic acids allow hereditary information to be stored?
Genetic information is carried in the linear sequence of nucleotides in DNA
RNA and DNA are composed of _________.
nucleotides
Nucleotides contain a sugar molecule
The sugar for RNA is ______.
The sugar for DNA is ______.
Ribose, Deoxyribose
RNA nucleotides contain one of the following nitrogen bases:
Uracil
Adenine
Cytosine
Guanine
DNA nucleotides contain one of the following nitrogen bases:
Thymine
Adenine
Cytosine
Guanine
Both DNA and RNA are _______.
polynucleotides
_______ form through a series of condensation reactions. A ___________ forms between the phosphate of one nucleotide, and the sugar of the second nucleotide.
Polynucleotides, covalent bond
The strong backbone in DNA and RNA is from covalently bonded _______ and ______ from the first nucleotide to the second nucleotide.
sugar, phosphate
Name the nucleotides in RNA:
Uracil, Adenine, Guanine, Cytosine
DNA is a double helix made of two _________ strands of nucleotides with two strands linked by ______ bonding between complementary base pairs.
antiparallel, hydrogen
Antiparallel:
The DNA strands run in opposite directions.
DNA has ____ strands. ____ sugar and the nitrogenous bases are.. ______.
2, deoxyribose, AGTC
RNA has ___ strands. _____ sugar and nitrogenous bases are ______.
(1), (ribose), U, A, G, C
Both ribose and deoxyribose are _______ sugars.
5 carbon pentose
What is the role of complementary base pairing in allowing genetic information to be replicated and expressed.
understand that complementarity is based on hydrogen bonding.
DNA replication is the process by which DNA makes a ____ of itself.
________ bonds form DNA between nucleotides during DNA replication.
copy, hydrogen
Thymine and Adenine form __ hydrogen bonds
2
Guanine and Cytosine form __ hydrogen bonds.
3
What are the 2 stages of protein synthesis.
Transcription: mRNA gets genetic code from DNA
Translation: the code from mRNA is used to make a sequence of amino acids in the ribosome
The number and length of chromosomes is highly ______ amongst different species.
variable
DNA molecules that contain genes are called _______.
chromosomes
______ are sequences of DNA, and code for specific proteins.
Genes
The nitrogenous base sequence determines the _________ in a protein.
amino acid sequence
All living organisms use the same ______ ,with a small number of exceptions. We all trace back to a _____________.
Genetic code, single ancestor
The enzymes involved in DNA replication (making copies of DNA) and transcription (producing mRNA) can only add nucleotides in the ___________.
5’ to 3’ direction
A DNA molecule has two antiparallel strands of DNA.
One strand runs from ______The other strand runs from ______.
5’ to 3’ , 3’ to 5’.
During translation, ribosomes move in _______ direction.
5’ to 3’
Chargaff’s data ____ the tetranucleotide hypothesis that there was a ______ sequence of the four bases in DNA.
falsified, repeating
Chargaff’s rule states that in any sample of DNA, the amount of guanine equals the amount of ______, and the amount of adenine equals the amount of _______.
Cytosine, thymine
Hershey Chase experiment - There was a debate whether DNA or ______ held Genetic material.
proteins
-Hershey and Chase used T2 bacteriophage viruses which consist of a _______________.
-The bacteriophages infect Escherichia coli (E.Coli) bacteria.
-When a T2 bacteriophage infects a bacterium, the DNA enters the cell, and the _____ ____ remains outside the cell.
DNA molecule and a protein coat. protein coat
Adenine–thymine (A–T) and cytosine–guanine (C–G) pairs have equal length, so the ____ _____ has the same three-dimensional structure, regardless of the base sequence.
DNA helix
Pyrimidines are _____.
Uracil, Thymine, Cytosine
James Watson and _________ discovered the structure of DNA.
Francis Crick
All organisms use the same ______ amino acids to build their proteins.
All the amino acids will have an _____ group (-NH2) and a _______ acid group (-COOH).
twenty, amine, carboxylic,
Each amino acid has a different ___ group. The R group determines the _______ properties and behavior of the amino acid.
R, chemical
Amino acids undergo _______ reactions to form dipeptides.
condensation
Amino acid + amino acid = ________ + water
dipeptide
A peptide bond forms between
__________________.
the carbon of the carboxylic acid group of one amino acid and the amine group of the second amino acid.
Formation of dipeptides: -OH and -H are removed from the amino acids, to form _____.
H20 (water)
The peptide bond is always between the __ and __ of neighbouring amino acids.
C, N
A polypeptide is a long chain of ________.
Polypeptides are formed by many _______ reactions at a ribosome during the process of translation
amino acids, condensation
Essential amino acids cannot be synthesized and must be obtained from _____.
Non-essential amino acids can be made from other amino acids.Vegan diets require attention to ensure essential amino acids are consumed.
food
Proteins are part of a healthy human ___.
Proteins are broken down to amino acids by the ______ system.
These amino acids are then used to _______ proteins for the body.
diet, digestive, synthesize
Humans require ___ amino acids to produce all of the proteins.
Humans can synthesize _____ of the amino acids, which are known as _________ amino acids
20, 11, non-essential (our body can make them)
The other nine amino acids that humans require are known as _______ amino acids, and must be consumed in the diet.
essential
Meat and animal products are considered _________, as they contain all nine of the essential amino acids.
complete proteins
Dairy products, beans, and tofu are examples of ___________.
proteins in foods
Most plant sources of protein ____ provide all of the essential amino acids.
don’t
Amino acids can occur in any order in a polypeptide, meaning that the variety of possible polypeptides is _____.
infinite
___________ is a conformational change in the shape of a molecule, such as a protein, resulting in the loss of function.
Denaturation
All proteins have a specific shape which determines the _______ of the protein.
Proteins can be denatured by ______ changes in pH and temperature.
function, extreme
R-groups determine the ______ of assembled polypeptides.
chemical properties
R groups can be ______ or ______.
hydrophobic, hydrophilic
The hydrophilic R groups are:
Polar or charged
Acidic or basic
The chemical interactions of the R groups in polypeptides determine the ____ of proteins which determines their function.
shape
Primary Protein Structure
amino acid sequence (chain)
Secondary Protein Structure
Local folding of the polypeptide chain into helices or sheets
Tertiary Protein Structure
three dimensional folding pattern of a protein due to side chain interactions
Quaternary Protein Structure
Protein consisting of more that one amino acid chain
the sequence of amino acids and the precise position of each amino acid within a structure determines the three-dimensional _____ of proteins. Proteins therefore have precise, predictable and ______ structures, despite their complexity.
shape, repeatable
The primary protein structure is the _____ and _______ of amino acids in a polypeptide.
number, sequence
The primary protein structure is determined by the nucleotide ____ sequence of a gene.
base
The amino acids in a polypeptide are joined together by ______ bonds through condensation reactions.
The precise sequence of amino acids in a polypeptide determines the shape of the polypeptide, due to _______ between R groups.
peptide, interactions
Proteins have _____ shapes based on their amino acid sequence.
predictable
_______________ is the folding of the polypeptide to form alpha helices and beta pleated sheets.
Secondary protein structure
Alpha helices and beta pleated sheets form due to _____ bonding between C=O of one amino acid and N-H of a second amino acid.
The hydrogen bonds occur at _______ intervals adding stability to the protein.
hydrogen, regular
____________ is the further folding of the polypeptide due to interactions between the R groups.
The tertiary protein structure
Interaction in the tertiary protein structure can cause the polypeptide to ___.
Ionic bonds with positive or negatively charged amine or carboxyl. covalent, hydrogen bonding. hydrophobic and hydrophilic interactions of R groups.
Disulfide bridges are bonds that form between the R groups of two _____ amino acids in a polypeptide. It is an amino acid with ____ within its R group.
cysteine, sulfur
Many proteins are _____.
Hydrophobic amino acids, with nonpolar R groups, cluster in a core of ______ proteins.
Hydrophilic amino acids, with polar or ____ R groups, are located on the outside of the protein.
soluble, globular, ionic
________________ exists in proteins composed of more than one polypeptide.
The quaternary structure
A _______ protein is a protein attached to a non-polypeptide group, known as a prosthetic group. Adult haemoglobin is an example of a ______ conjugated protein. The function of haemoglobin is to carry oxygen within ______.
conjugated, globular, red blood cells
Non-conjugated proteins are composed of only ______.
_____ is an example of a non-conjugated protein. It is a globular protein composed of two polypeptide chains linked by two ____ _____.
polypeptides, insulin, disulfide bridges
_____ is a hormone that helps to regulate blood glucose levels, by causing the liver to remove glucose from the blood.
Insulin
Proteins can be classified as either ____ or _____.
globular, fibrous
Insulin is a _____ protein and collagen is a _____ protein. Insulin is ____ while collagen is long and narrow.
globular, fibrous, spherical
Insulin and Collagen are composed of amino acids joined by peptide bonds during the process of translation on ribosomes. They have a quaternary structure with more than one polypeptide.
Similar
Collagen has a _____ amino acid sequence while insulin has a irregular sequence with _________.
repetitive, hydrophobic amino acids in the core.
Insulin is _____ while collagen is insoluble.
soluble
______: Two polypeptides held together by disulfide bonds
Insulin
_____: Three polypeptides held together by hydrogen bonds
Collagen
______ is a hormone with a specific globular shape, with a binding site for receptors on target cells.
Insulin
The three polypeptides in ______ form flexible fibres with high tensile strength and elasticity which provides structural support to body tissues.
collagen
A conjugated protein is a protein attached to a non-polypeptide group, known as a ________.
prosthetic group
