High School Biology : Introductory Topics

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #1 : Understanding Properties Of Water

Which of the following organs is responsible for detoxification?

Possible Answers:

Mitochondria

Ribosomes

Vacuoles

Nucleus

Peroxizomes

Correct answer:

Peroxizomes

Explanation:

Peroxisomes are responsible for detoxification. They contain many enzymes that breakdown lipids and amino acids. Additionally, they breakdown toxins like alcohol in the cells of the liver. 

Example Question #51 : High School Biology

All organic compounds contain which of the following elements? 

Possible Answers:

Sulfur 

Nitrogen 

Carbon

Oxygen

Hydrogen

Correct answer:

Carbon

Explanation:

Organic compounds are defined as solids, liquids, or gases whose molecular structure includes carbon. Inorganic compounds, in contrast, do not contain carbon. Organic compounds might contain other elements, like hydrogen and oxygen, but not all compounds need these other elements to be considered organic.

Example Question #1 : Understanding Properties Of Carbon

What are the four most abundant elements found in living organisms?

Possible Answers:

Hydrogen, carbon, sulfur, nitrogen

Hydrogen, nitrogen, oxygen, iron

Carbon, hydrogen, oxygen, sulfur

Carbon, phosphorous, hydrogen, oxygen

Hydrogen, carbon, oxygen, nitrogen

Correct answer:

Hydrogen, carbon, oxygen, nitrogen

Explanation:

Living organisms are primarily made up of organic molecules, which contain carbon. The six most prevalent elements in living organisms are carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur, in that order.

Carbon and hydrogen are found in the basic monomer structure of all biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids). Nitrogen is found in amino acids, which form proteins, and the nitrogenous bases in nucleic acids (DNA and RNA). Oxygen is found in all biological macromolecules. Phosphorous is found in nucleic acids and lipids, such as phospholipids in the cell membrane. Sulfur is found in cysteine, a specific amino acid.

Example Question #1 : Understanding Properties Of Carbon

Why does carbon tend to form four molecular bonds?

Possible Answers:

It donates four electrons to become more stable

It accepts four electrons to become more stable

It must balance its partial negative charge

It is highly electronegative

It has four valence electrons

Correct answer:

It has four valence electrons

Explanation:

Since carbon is in group IV of the periodic table, we know that it has four valence electrons. Most elements (with the exceptions of hydrogen and helium) are most stable when they have filled their valence shell with eight electrons. For carbon to fill its valence shell, it needs to make four covalent bonds. Remember that carbon is not very electronegative and only very rarely (if ever) forms ionic bonds. This means that carbon will not donate, nor accept electrons; rather it will share them with other atoms to form molecules.

Example Question #13 : Attributes Of Life

One carbon atom has the ability to bind with __________ other atoms.

Possible Answers:

Correct answer:

Explanation:

Carbon has four electrons in its valence shell which means it needs four more to have a stable octet. This means that the maximum number of bonds it can form is four when each bond only contributes one electron to the relationship.

Example Question #52 : High School Biology

How many valence electrons does a carbon atom have?

Possible Answers:

8

4

6

3

2

Correct answer:

4

Explanation:

One of the reasons carbon is so ubiquitous in biological structures is the fact that it has four valence electrons, meaning it likes to form four bonds to complete an octet in its outer shell. Being able to form four bonds means that it can bind to multiple other atoms covalently and with high stability.

Example Question #53 : High School Biology

All organic compounds contain which of the following elements? 

Possible Answers:

Hydrogen

Nitrogen 

Oxygen

Carbon

Correct answer:

Carbon

Explanation:

Organic compounds are defined as solids, liquids, or gases whose molecular structure includes carbon. Inorganic compounds, in contrast, do not contain carbon. Organic compounds might contain other elements, like hydrogen and oxygen, but not all compounds need these other elements to be considered organic.

Example Question #1 : Understanding Biological Equilibrium

Which of the following is true when the body is under homeostasis?

Possible Answers:

The body cannot generate its own heat in very cold conditions

The body is under dynamic equilibrium

The body is able to self-sustain without anything from the environment

The body is at an appropriate core temperature and no longer needs to regulate body temperature

The body stops digesting foods

Correct answer:

The body is under dynamic equilibrium

Explanation:

Homeostasis means "staying still" in Greek, and is a property of the human body that describes when functions and processes allow the conditions of the body to remain stable. This does not mean that the body ceases any function. It simply means that the current functions of the body are able to keep the body at a stable condition.

For example, blood glucose in the body is under homeostatic regulation by the hormones insulin and glucagon. Both hormones are always in circulation, meaning that glucose is both being released into the blood and begin taken from the blood for storage. The result is a stable amount of glucose because both processes occur together. When a meal causes blood glucose to rise, insulin levels increase and glucagon levels decrease to accommodate the change, but both hormones are still present. This creates a dynamic equilibrium in which glucose is both retained and released, allowing a stable amount to be in circulation.

Example Question #1 : Feedback And Homeostasis

Which of following correctly describes how a catalyst affects a chemical reaction?

Possible Answers:

Slows down a chemical reaction by increasing the activation energy

Speeds up a chemical reaction by increasing the activation energy

Speeds up a chemical reaction by lowering the activation energy

Slows down a chemical reaction by lowering the activation energy

Has no effect on the speed of the chemical reaction, but increases the amount of product produced

Correct answer:

Speeds up a chemical reaction by lowering the activation energy

Explanation:

A catalyst is a substance that increases the rate of a reaction by lowering the activation energy needed for the given chemical reaction to occur. Activation energy is the input of energy required for a reaction to occur. This energy is used to break the bonds of the reactant, allowing the reaction to proceed. If a catalyst lowers the amount of energy needed for a reaction to occur, the reaction can occur at a faster rate because it reaches that lower energy level more quickly than it would have the original higher energy level.

Example Question #1 : Feedback And Homeostasis

Which is not an example of homeostasis?

Possible Answers:

The kidneys work to remove excess salt, urea, and water from the bloodstream

Mitochondria create ATP through proton pumps in order to power the cellular processes

Oxygen content in the bloodstream is low, so the heart pumps faster and speed/depth of breathing increases

Insulin is released by the pancreas to encourage cells to retain their glucose instead of releasing it into the blood stream

Warm blooded (endothermic) animals sweat to release heat, or shiver to increase metabolic activity and increase body temperature

Correct answer:

Mitochondria create ATP through proton pumps in order to power the cellular processes

Explanation:

The situation describing ATP production is the only one in which there is no problem in need of correction. Homeostasis requires maintenance of a balance. While ATP production is an essential process, the simple function of the ATP synthase proton pump is not directly related to biological stability in homeostasis.

All other answers describe situations in which the body corrects a problem or situation and restores balance to internal mechanisms. This is the nature of homeostasis—there is a disruption to the balance, and the body adjusts in order to keep the processes running smoothly.

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