Water and Carbon
What type of bond holds the atoms together within a water molecule?
Polar covalent bonds.
What is the name of the simplest carbohydrate building block?
Monosaccharide.
Which part of a phospholipid interacts with water?
The hydrophilic head.
What are the building blocks of DNA and RNA called?
Nucleotides
What are the building blocks of proteins called?
Amino Acids
In a water molecule, which atom has a greater attraction for shared electrons: oxygen or hydrogen?
Oxygen
What is glucose?
A monosaccharide, or simple sugar.
What molecule stores long term energy in a living organism?
A triglyceride.
What three components make up a nucleotide?
A phosphate group, a five-carbon sugar, and a nitrogen-containing base.
What part of an amino acid varies between different amino acids?
The R group.
Why is water considered a polar molecule?
It's electrons are shared unequally
What is the difference between starch and cellulose in plants?
Starch stores energy; cellulose provides structural support.
What are the two main components that combine to form a triglyceride?
One glycerol and three fatty acids.
Which nitrogenous base is found in RNA instead of thymine?
Uracil
What is the name for a chain of amino acids?
A polypeptide.
What type of attraction forms between the partially positive hydrogen of one water molecule and the partially negative oxygen of another?
A hydrogen bond.
A plant needs to store energy for later use. Which carbohydrate did we study that serves this role?
Starch
What is the structural difference between a steroid and a triglyceride?
A steroid has four fused carbon rings; a triglyceride has glycerol attached to three fatty acids.
Which component of a nucleotide differs among nucleotides and contributes to the information in a nucleic acid?
The nitrogenous base.
What is the difference between a protein's primary structure and tertiary structure?
Primary structure is the amino acid sequence; tertiary structure is the overall three-dimensional shape of one polypeptide/protein.
Two molecules have the same molecular formula but different arrangements of their atoms. What are these molecules called, and why might they have different properties?
Structural isomers; their atoms are connected differently, which can change their properties and interactions.
Starch and cellulose are both polysaccharides made from sugar units, yet they perform different functions. What does this tell us about biological molecules?
Being made from similar building blocks does not guarantee the same properties or function; molecular structure and arrangement matter.
A fatty acid has one or more carbon–carbon double bonds. Is it saturated or unsaturated?
Unsaturated.
Why is the sequence A–T–G–C biologically different from A–G–T–C, even though both contain the same four bases?
The order of the bases is what matters, since they differ, the sequences encode different information.
A mutation replaces one amino acid with another that has a different R group. Explain one possible chain of events that could change protein function.
Folding/3D shape will change thus likely changing the functions of the protein (could increase/decrease polarity/nonpolarity/charges)
A molecule contains many carbon atoms connected in a chain. What is this carbon framework called?
A carbon skeleton.
A sample tests positive for starch with Lugol's iodine but negative with Benedict's reagent. Does this mean the sample contains no carbohydrates? Explain.
No. The results provide evidence of starch, while the negative Benedict's result indicates no detectable reducing sugar under the test conditions. Starch is a carbohydrate even though it does not produce a positive Benedict's result.
Butter is generally solid at room temperature, while olive oil is liquid. How can differences in their fatty acids help explain this?
Butter generally contains a higher proportion of saturated fatty acids, which pack more tightly.
Olive oil generally has more unsaturated fatty acids, whose double bonds create kinks that hinder packing and lower the melting point.
Tell me the complementary DNA sequence for:
5′–ATGC–3′
including the direction of the complementary strand.
3′–TACG–5′.
What stabilizes alpha helices and beta sheets?
Hydrogen bonds involving the polypeptide backbone.