2024 Fall Semester Review - PreAP Biology

Front

What is active transport?

Back

Active transport is the process of moving molecules across a cell membrane against their concentration gradient, using energy (usually from ATP) and protein pumps.

Front

What is passive transport?

Back

Passive transport is the movement of molecules across a cell membrane without the use of energy, typically moving down their concentration gradient.

Front

What is the main difference between active transport and passive transport?

Back

Active transport requires energy to move molecules against their concentration gradient, while passive transport does not require energy and moves molecules down their gradient.

Front

What is a codon?

Back

A codon is a sequence of three nucleotides in mRNA that corresponds to a specific amino acid or a stop signal during protein synthesis.

Front

What amino acid is represented by the codon UUA?

Back

Leucine.

Front

What is a frameshift mutation?

Back

A frameshift mutation occurs when nucleotides are inserted or deleted from the DNA sequence, causing a shift in the reading frame of the codons.

Front

Why do insertion and deletion mutations often have more severe effects than substitution mutations?

Back

Insertion and deletion mutations cause a frameshift, altering all downstream codons, which can significantly change the resulting protein.

Front

What is the role of protein pumps in active transport?

Back

Protein pumps are integral membrane proteins that use energy to transport ions or molecules across the cell membrane against their concentration gradient.

Front

What is the concentration gradient?

Back

The concentration gradient is the difference in the concentration of a substance across a space, which drives the movement of molecules during diffusion and osmosis.

Front

What is the structure of DNA?

Back

DNA is a double helix composed of two strands of nucleotides, each containing a sugar, a phosphate group, and a nitrogenous base.