Organic Molecules
What two elements must be present in an organic molecule?
Carbon and hydrogen
What carbohydrate is the preferred energy source for cells?
Glucose
What is the monomer of a protein?
Amino acid
What is the main component of the plasma membrane?
Phospholipids
Which organelle is known as the control center of the cell?
Nucleus
What is the term for molecules with the same chemical formula but different arrangements of atoms?
Isomers
Animals store excess glucose in what form?
Glycogen
What type of bond links amino acids together?
Peptide bond
Which part of a phospholipid is hydrophilic?
Phosphate head
What organelle produces proteins?
Ribosomes
What functional group is found in amino acids and proteins and is represented by -NH₂?
Amino group
Plant cell walls are primarily composed of what polysaccharide?
Cellulose
What level of protein structure is the amino acid sequence?
Primary structure
Why is the membrane described as a "fluid mosaic"?
Proteins are embedded within a fluid phospholipid bilayer.
Which organelle modifies, sorts, and packages proteins?
Golgi apparatus
Explain why carbon can form such a large variety of molecules.
Carbon has four valence electrons and can form four covalent bonds.
Why are lipids generally insoluble in water?
They contain long nonpolar hydrocarbon chains.
What process causes proteins to lose their shape and function?
Denaturation
Which membrane protein receives signals from outside the cell?
Receptor protein
Which organelle digests wastes and damaged organelles?
Lysosome
A mutation changes a phosphate-containing nucleotide. Which class of biological molecules is directly affected?
Nucleic acids
Compare saturated and unsaturated fats.
Saturated fats contain no double bonds and are usually solid at room temperature; unsaturated fats contain one or more double bonds and are usually liquid.
Explain how a mutation in DNA can affect protein function.
DNA determines amino acid sequence, which determines protein shape and ultimately function.
A molecule moves against its concentration gradient. Which type of membrane protein would most likely be involved?
Transport protein
A cell produces large amounts of digestive enzymes. Which organelle would be especially abundant?
Rough ER