Biological Molecules Flashcards
List the ways mRNA is different to DNA.
1) mRNA is single stranded 2) Has uracil instead of thymine 3) It is not helical 4) It is a smaller/shorter molecule 5) Contains ribose instead of deoxyribose
Why is mRNA shorter than DNA?
It only copies one section of DNA (a gene) whereas DNA has lots of genes.
How does heat affect a proteins structure?
Increased kinetic energy makes the protein vibrate causing the weak hydrogen bonds to break, changing its 3D shape and denaturing the protein.
What does an inorganic ion cofactor do in a reaction?
Bonds with the substrate or enzyme to increase the rate of reaction.
What bond joins amino acids together in a polypeptide chain?
Peptide bond. C=ON-H
Name the 4 bonds that can occur in the tertiary structure of a protein.
1) Disulfide bonds 2) ionic bonds 3) hydrogen bonds 4) hydrophobic/hydrophilic interactions
True/False: Fibrous proteins are soluble.
False. They are insoluble and globular proteins are soluble.
What is the sugar in a nucleotide of DNA?
Deoxyribose (a pentose monosaccharide)
What bond joins nucleotides to each other?
Phosphodiester bonds on C3 and C5.
Which of the bases are purines?
Adenine and guanine.
Which pair of bases has 3 hydrogen bonds?
Cytosine and guanine.
What does polymerase do in semi-conservative replication?
Joins the nucleotides together using phosphodiester bonds.
What is a codon?
Sequence of 3 bases. Each codon codes for an amino acid.
Name the section of DNA testing that codes for a entire protein.
Gene
What is the role of tRNA in translation?
It carries the amino acids to its corresponding codon.
What is ATP made of?
3 phosphate groups, nitrogenous base (adenine) and ribose sugar.
Why is ice being less dense than water good for organisms?
Because it insulates the water below and helps regulate their environment.
When two monosaccharides react what is the bond that joins them?
Glycosidic bond.
True/False: Amylopectin has many branches.
True. It has 1,4 and 1,6 glycosidic bonds which causes branching.
Why is cellulose in a rigid straight chain?
Because it is made of beta glucose where every other one is flipped.
If Benedict’s reagent is added to a substance and it produces a brick red precipitate, what is in the substance?
A monosaccharide (reducing sugar) eg. Glucose
When iodine is added to a substance and it changes from yellow to black, what is in the substance?
Starch
What is a triglyceride made of and what is the bond that joins them?
1 glycerol molecule and 3 fatty acids joined by an ester bond.
Name three roles of lipids.
1) phospholipid bilayer in membranes 2) waterproofing the surface of leaves 3) thermal insulation