Solutions!
What happens if you drink seawater (hypertonic)?
Your cells lose water and shrink.
What is the main function of DNA in the cell?
DNA stores genetic information and provides instructions for making proteins.
What is the main difference between active and passive transport?
Active transport requires energy (ATP), while passive transport does not require energy.
What is the purpose of mitosis?
produce two identical daughter cells for growth, repair, and replacement of body cells.
What is the Central Dogma of Molecular Biology?
It states that genetic information flows from DNA → RNA → Protein.
What happens to a cell in a hypertonic solution?
shrinks
How does DNA control the structure of proteins?
The sequence of DNA bases determines the sequence of amino acids in a protein.
Which direction do molecules move in passive transport?
From high concentration to low concentration (down the concentration gradient).
What happens during prophase?
Chromosomes condense, spindle fibers form, and the nuclear envelope begins to break down.
What molecule carries the genetic code from DNA to the ribosome?
mRNA (messenger RNA).
What happens to a cell in an isotonic solution?
It stays the same size.
What are the building blocks of proteins, and how are they linked together?
The building blocks are amino acids, and they are linked by peptide bonds.
Give one example of passive transport in cells.
Diffusion of oxygen into a cell or osmosis of water.
What happens during telophase and cytokinesis?
The nuclear envelope reforms around chromosomes, and the cytoplasm divides, creating two new cells.
How does the genetic code ensure the correct protein is made during translation?
The genetic code uses codons (three-base sequences on mRNA) that match with anticodons on tRNA, guaranteeing the correct amino acid sequence.
Why does a red blood cell placed in a hypertonic solution shrink?
Because water moves out of the cell by osmosis.
Why are proteins important for cells? (function)
Proteins act as enzymes, hormones, structural components, and transport molecules needed for life.
Give one example of active transport in cells.
The sodium-potassium pump, which moves sodium out of the cell and potassium in, using ATP.
What role do spindle fibers and centrosomes play in metaphase?
Spindle fibers attach to the centromeres of chromosomes, aligning them at the cell’s equator to ensure even separation.
How can errors in RNA processing affect the final protein even if the DNA sequence is correct?
Mistakes in splicing, capping, or poly-A tail addition can create faulty mRNA, producing a nonfunctional or incorrect protein, even though the DNA is unchanged.
Why do athletes receive isotonic sports drinks instead of pure water after heavy sweating?
Because isotonic drinks replace water and electrolytes without making cells swell or shrink.
What happens during translation?
The ribosome reads the mRNA code, tRNA delivers amino acids, and the amino acids are linked together to make a protein.
Why is active transport important for cells?
lets cells move substances against their concentration gradient, which is needed for functions like nerve impulses and muscle contractions.
What is the difference between mitosis and cytokinesis?
Mitosis divides the nucleus and chromosomes, while cytokinesis divides the cytoplasm, completing cell division.
What might happen if a mutation changes one DNA base in a gene?
It could cause a different amino acid to be inserted (missense mutation), create a stop codon (nonsense mutation), or have no effect (silent mutation), which may alter or damage the protein’s function.