College Biology Chapters 4-6 Test

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What is a protein?

Macromolecule made of amino acid chains

Functions of proteins

structural, regulatory, contractile, protective, transportation, storage, membranes, toxins, enzymes

What might denature a protein?

changes in pH or temperature, ultimately changes in shape

What are amino acids?

monomer of proteins

Where do amino acids differ from each other?

R group

What is the basic structure of an amino acid?

[left to right] amino group, central carbon, carboxyl group, and r side chain on the bottom

What is an essential amino acid?

amino acids that can’t be made by the organism and has to be obtained through diet

What bonds amino acids together?

peptide bonds through dehydration synthesis reactions (produces h2o)

How do cells break proteins down into amino acids?

hydrolysis reactions

What is the N terminal?

side of the amino acid chain with the amino group

What is the C terminal?

side of the amino acid chain with the carboxyl group

Where do peptide bonds occur on amino acids?

between amino and carboxyl groups

What is a peptide backbone?

chain of amino acids

What’s important about the sequence of amino acids?

determines size, shape, function of proteins

What is the active site of an enzyme?

place for substrate to bind

What is the primary structure of proteins?

order of amino acid chain

What is the secondary structure of a protein?

the folding in alpha helix or beta pleated sheet structures

What is the tertiary structure of proteins?

3-dimensional structure made by interactions between R-groups

What is a chaperone?

molecule that helps proteins bond

What is the quaternary structure of proteins?

interaction of subunits/different polypeptides into a larger structure

What do enzymes do?

catalyze reactions

What is activation energy in enzymes?

amount of energy needed to get started

What might damage an enzyme?

pH or temperature issues

What is induced fit?

enzymes and substrates can change shape a teeny tiny bit to fit better and confirm that they are “meant to be”

What is Gibbs free energy?

measure of usable energy available to do work

What is an exergonic reaction?

reactants have more free energy than products (energy EXITS the system)

what is an endergonic reaction?

reactants have less free energy than products (energy is ENTERING the system)

What is a common source of activation energy?

heat from environment

What is competitive inhibition?

inhibitor binds to active site of an enzyme instead of the substrate

What is allosteric inhibition?

inhibitor binds to NOT active site, changing the shape

What is a cofactor?

helper molecule that is an inorganic ion

What is a coenzyme?

helper molecule that is an organic molecule like a vitamin

What is a metabolic pathway?

chain of enzyme-substrate reactions where one product becomes the substrate for the next enzyme

What is negative feedback inhibition?

product of one of the last enzymes in a metabolic pathway inhibits one of the earlier enzymes

What is the monomer of nucleic acids?

nucleotides

What is a nucleotide made of?

5-carbon sugar (pentose), a nitrogenous base (A,C,T/U,G), phosphate group(s)

Where is the nitrogenous base attached to the pentose sugar in a nucleotide?

1’ carbon

Where is the phosphate group attached to the pentose sugar in a nucleotide?

5’ carbon

What is always attached to the 3’ carbon of a pentose sugar in a nucleotide?

hydroxyl group

What sugar is RNA made of? What’s the difference from DNA?

Ribose; has a hydroxyl group on the 2’ carbon

What is the sugar for DNA? What’s the difference from RNA?

deoxyribose; only a hydrogen on the 2’ carbon

What are purines?

2 carbon-nitrogen rings in a nitrogenous base

What are the purine nitrogenous bases?

Adenine and guanine

What is a pyrimidine?

1 carbon-nitrogen ring in a nitrogenous base

What are the pyrimidine nitrogenous bases?

Cytosine, Thymine, and Uracil

What combines nucleic acids?

phosphodiester bonds between 3’ hydroxyl and 5’ phosphate

Where are nucleotides always added to create a nucleic acid chain?

ALWAYS added at the 3’ end

What is the structure of DNA?

double helix

What does complementary strands mean?

base pairs complement each other on opposing strands A/T(U) and C/G

Why is it significant that DNA is complementary?

allows for replication

What does antiparallel mean?

double helix strands run in opposite directions with 5’ of one strand at the top, and the 3’ end at the top from the other strand

What is a gene?

segment of DNA that codes for one polypeptide chain

what are histones?

things DNA wrap around to form chromosomes

what are chromosomes?

lots of genes 👍👍

How many chromosomes do prokaryotes have?

1

What is a plasmid?

mini sorta chromosomes in prokaryotes in addition to their one full one

What is a genome?

entire genetic content of a cell

Function of DNA

carries genetic information

Function of RNA

protein synthesis

Location of DNA (eukaryotes)

nucleus

Location of DNA (prokaryotes)

nucleoid/cytoplasm

Location of RNA

cytoplasm/not nucleus

Structure of RNA

single stranded (most times)

Nucleotides of DNA

AT, CG

Nucleotides of RNA

AU, CG

what does mRNA do?

copies the genetic code from the DNA and brings it to synthesizing molecules. it is a complement of the template DNA and a copy (except U for T) of the coding strand

What is the template strand?

which DNA strand mRNA bases it’s code off of

What is the coding strand?

complement to template strand, identical to mRNA

What is ATP?

adenosine triphosphate, energy currency for cells

Structure of ATP

[left to right] 3 phosphate groups, ribose, adenine

How does ATP release energy?

loses a phosphate group, turns into ADP

How does ADP gain energy?

reattaches a third phosphate

What is energy coupling?

exergonic reaction of hydrolyzing ATP drives an endergonic reaction

What is the central dogma of molecular biology?

DNA—-transcription—-mRNA—-translation—-proteins

what is a codon?

3 base segment of DNA/RNA

How many codons are there

64

What are the stop codons?

UAG, UAA, UGA

What is the start codon?

AUG

what does unambiguous mean in genetic code?

1 codon gives 1 amino acid

what does universal genetic code mean?

same genetic code for the same proteins in almost all species

what does redundant genetic code mean?

amino acids coded by more than one codon

what is a mutation?

heritable change in the DNA

What is a point mutation?

change in 1 base

What is a missense mutation?

changes the amino acid

What is a nonsense mutation?

changes to a stop codon

What is a silent mutation?

different codon for the same amino acid

What is a frameshift mutation?

addition or subtraction of a base pair that alters the subsequent amino acid codes

What is a chromosomal mutation?

changes large sections of genes, not just one or two

What is (chromosomal) deletion?

missing a chromosome

What is (chromosomal) duplication?

extra chromosome

What is (chromosomal) inversion?

part of a chromosome is backward

What is (chromosomal) translocation?

part of one chromosome is on another

What is a beneficial mutation?

increases fitness

What is a neutral mutation?

does not increase or decrease fitness, like silent mutations

what is a deleterious mutation?

decreases fitness

What is transcription?

DNA—mRNA; mRNA gene copy

Where does transcription take place (eukaryotes)?

nucleus

Where does transcription take place (prokaryotes)?

cytoplasm

What is the promoter?

specific sequence that indicates where to begin transcription and says which strand is the template strand.

Where does transcription machinery bind (prokaryotes)?

promoter