Cells
Which cell structure controls what enters and leaves the cell?
Cell Membrane
Which body system transports oxygen and nutrients throughout the body?
The circulatory system
What molecule carries genetic information?
DNA.
Which nutrient is the body's main source of energy?
Carbohydrates
What is the process in which organisms with helpful inherited traits are more likely to survive and reproduce.
Natural Selection
What is the basic unit of life?
The cell
How do the respiratory and circulatory systems work together?
The respiratory system brings oxygen into the lungs, and the circulatory system transports that oxygen to body cells.
What is a gene?
A segment of DNA that contains instructions for a particular product or influences a trait.
A student eats a meal containing whole-grain bread, eggs, and fruit.
Question: Identify one nutrient supplied by each food and explain one function of that nutrient in the body.
Answer: Bread provides carbohydrates for energy; eggs provide protein for building and repairing tissues; fruit provides vitamins and other nutrients that support normal body functions.
What is an inherited trait that helps an organism survive or reproduce in its environment?
An adaptation
What is the main difference between plant cells and animal cells?
Plant cells have a cell wall and chloroplasts; animal cells do not.
If a person's kidneys stop working properly, which body function is most directly affected?
Removing wastes and excess water from the blood.
Two parents carry a recessive allele for a genetic condition but do not have the condition themselves. Can their child have the condition?
Yes. If the child inherits the recessive allele from both parents, the child can have the condition.
Why does the human body need water?
Water helps regulate body temperature, transport nutrients, remove waste, and support normal cell functions
Why do some bacteria survive when antibiotics are used?
Some bacteria have genetic variations that make them resistant to the antibiotic. They survive and reproduce, passing on resistance.
A mutation damages the ribosomes in a cell. The cell still has a nucleus and mitochondria, but many of its normal functions begin to fail. Explain why damage to ribosomes could affect multiple functions of the cell.
Ribosomes build proteins. Proteins perform many essential functions, including acting as enzymes, transporting substances, and providing structural support. Without enough functional proteins, many cellular processes are disrupted.
Why might a person breathe faster during exercise?
The body needs more oxygen and must remove more carbon dioxide as cells produce energy.
student claims that DNA and RNA contain exactly the same bases because both carry genetic information.
Question: Explain why the student's claim is incorrect.
DNA contains adenine, thymine, cytosine, and guanine. RNA contains adenine, uracil, cytosine, and guanine. RNA uses uracil instead of thymine.
Explain the difference between an infectious disease and a noninfectious disease. Give one example of each.
An infectious disease is caused by a pathogen, such as influenza. A noninfectious disease is not caused by a transmissible pathogen, such as type 2 diabetes.
A population of rabbits includes white and brown rabbits. In a snowy environment, white rabbits are harder for predators to see. Over many generations, what might happen to the population, and why?
White rabbits may become more common because they are less visible to predators and may survive and reproduce more successfully
Why do muscle cells contain many mitochondria compared with some other types of cells?
Muscle cells need large amounts of energy to contract and move the body.
A person has a damaged pancreas and cannot produce enough insulin. After eating a meal, the person's blood glucose remains unusually high. Explain why damage to the pancreas can affect blood glucose levels.
Insulin helps regulate blood glucose by allowing certain cells to take up glucose and by reducing glucose release into the blood. Without enough insulin, blood glucose can remain elevated
A DNA template strand reads:
T – A – C – C – T – A
A student writes this mRNA sequence:
A – T – G – G – A – T
Question: Is the student's mRNA sequence correct? If not, identify the error.
No! A - U - G - G - A - U
Remember for RNA, we use U instead of T
Two patients have different illnesses. Patient A has influenza caused by a virus. Patient B has a bacterial infection diagnosed by a doctor.
Question: Why might antibiotics help Patient B but not Patient A?
Antibiotics target bacteria and their structures or processes. They do not treat influenza because influenza is caused by a virus.
A student says, “Animals evolve because they try to change to survive.” Explain why this statement is incorrect.
Evolution does not happen because organisms intentionally change. Individuals have inherited variations, and natural selection makes helpful traits more common in a population over many generations.