The physical appearance or _____ of an organism is determined by a set of alleles.

A. Cell wall

B. Ribosome

C. Cytoplasm

D. Golgi apparatus

Only plant cells have cell walls, which help protect the cell and provide structural support.  The cell wall also enforces the overall structural integrity of the plant cell, and it is found outside the cell membrane. The next organelle is a chloroplast. It is found in the cytoplasm of only plant cells. Chloroplasts are photosynthetic compounds used to make food for plant cells by harnessing energy from the sun. These organelles play a role in photosynthesis.

A. Combination

B. Decomposition

C. Hydrolysis

D. Neutralization

A neutralization reaction is a type of acid-base reaction where an acid and base react to form a salt and water. 

In an aqueous solution, a base increases the hydroxide concentration (OH–), while an acid increases the hydrogen ion (H+) concentration. Sometimes, neutralization reactions also occur. This type of reaction happens when an acid and a base react with each other to form water and salt. Salt is typically defined as an ionic compound that includes any cation except H+ and any anion except OH–. Consider the following example of a neutralization reaction between hydrobromic acid (HBr) and potassium hydroxide (KOH).

HBr+KOH→KBr+H2O

Not all neutralization reactions proceed in the manner where all reactants are in the aqueous phase. In some chemical reactions, one reactant may be a solid. The neutralization reaction can still proceed to completion.

A. antibody

B. pathogen

C. trigger

D. vaccination

Pathogen is an infectious foreign body that enters the body and causes disease or illness to the person. There are five types of pathogens: viruses, bacteria, fungi, protozoa, and worms. Pathogens have antigen proteins found on their surface and are unique to each pathogen.

Antibody is a protein produced by the body’s immune system when it detects harmful substances (antigens). There are many different antibodies found in the body. Each one is unique and protects the body against the specific antigen that it detects at any given time. If there are no antibodies for a specific antigen, the more likely you are to develop an illness.

Vaccinations are the introduction of a dead or disabled pathogen or of a harmless microbe with the protein of a pathogen on its surface into the body. Often administered through needle injection, to stimulate the immune system to produce immunity to a specific disease Immunity protects the body from a disease when exposed to it.

There are four types of immunity: natural/passive, natural/active, artificial/passive, and artificial/ active.

• Natural/passive – Babies receive immunities from breastmilk.
• Natural/active – The body produces antibodies to combat an illness when a person becomes sick.
• Artificial/passive – This immunity is temporary and requires doses of serum to maintain the immunity.
• Artificial/active – A vaccination provides artificial/active immunity.

A. carbon dioxide

B. minerals in soil

C. decaying matter

D. sugar molecules

Autotrophs are organisms that use basic raw materials in nature, like the sun, to make energy-rich biomolecules. Minerals are naturally inorganic.

Autotrophs are organisms that make energy-rich biomolecules from raw material in nature. They do this by using basic energy sources such the sun. This explains why most autotrophs rely on photosynthesis to transform sunlight into usable food that can produce energy necessary for life. Plants and certain species of bacteria are autotrophs.

A. A functional system of the body

B. Blood flow to every cell in the body

C. A relatively constant environment within the body

D. Neural pathways that have integrated into the body

Homeostasis is the existence and maintenance of a relatively constant environment within the body. Each cell of the body is surrounded by a small amount of fluid, and the normal functions of each cell depend on the maintenance of its fluid environment within a narrow range of conditions, including temperature, volume, and chemical content. These conditions are known as variables. For example, body temperature is a variable that can increase in a hot environment or decrease in a cold environment.

There are two types of feedback mechanisms in the human body: negative and positive.

• Negative Feedback: Most systems of the body are regulated by negative feedback mechanisms, which maintain homeostasis. Negative means that any deviation from the set point is made smaller or is resisted. The maintenance of normal blood pressure is a negative-feedback mechanism. Normal blood pressure is important because it is responsible for moving blood from the heart to tissues.
• Positive Feedback: Positive-feedback mechanisms are not homeostatic and are rare in healthy individuals. Positive means that when a deviation from a normal value occurs, the response of the system is to make the deviation even greater. Positive feedback therefore usually creates a cycle leading away from homeostasis and, in some cases, results in death. Inadequate delivery of blood to cardiac muscle is an example of positive feedback.

A. Alveolus

B. Capillary

C. Lung

D. Trachea

The primary function of the respiratory system is to provide oxygen to and remove carbon dioxide from the body. In addition to gas exchange, the respiratory system enables a person to breathe. Breathing, or inhalation, is essential to life. It is the mechanism that provides oxygen to the body. Without oxygen, cells are unable to perform their functions necessary to keep the body alive. The primary muscle of inspiration is the diaphragm. Known as the chest cavity, this dome shaped structure flattens when it contracts. The rib cage moves outward, allowing outside air to be drawn into the lungs. During relaxation, the diaphragm returns to its dome shape and the rib cage moves back to its natural position. This causes the chest cavity to push air out of the lungs.

The respiratory system can be functionally divided into two parts:

• Air-conducting portion: Air is delivered to the lungs. This region consists of the upper and lower respiratory tract—specifically, the larynx, trachea, bronchi, and bronchioles.
• Gas exchange portion: Gas exchange takes place between the air and the blood. This portion includes the lungs, alveoli, and capillaries.

A. As a result, Mendel developed several theories that have since been disproved.

B. Mendel realized he was on an incorrect track, which led him to other experimental media

C. As a result, Mendel developed foundational conclusions that are still valued and followed today.

D. Mendel collaborated with others interested in genetics to develop heredity guidelines we still use today

Mendel developed theories of genetics that scientists around the world use today.

From experiments with garden peas, Mendel developed a simple set of rules that accurately predicted patterns of heredity. He discovered that plants either self-pollinate or cross-pollinate, when the pollen from one plant fertilizes the pistil of another plant. He also discovered that traits are either dominant or recessive. Dominant traits are expressed, and recessive traits are hidden.

Mendel’s Theory of Heredity

To explain his results, Mendel proposed a theory that has become the foundation of the science of genetics. The theory has five elements:

• Parents do not transmit traits directly to their offspring. Rather, they pass on units of information called genes.
• For each trait, an individual has two factors: one from each parent. If the two factors have the same information, the individual is homozygous for that trait. If the two factors are different, the individual is heterozygous for that trait. Each copy of a factor, or gene, is called an allele.
• The alleles determine the physical appearance, or phenotype. The set of alleles an individual has is its genotype.
• An individual receives one allele from each parent.
• The presence of an allele does not guarantee that the trait will be expressed.

A. Centromere

B. Gamete

C. Homologue

D. Ribose

The protein disc that holds two sister chromatids together is what collectively makes a chromosome. A gene is a segment of DNA, deoxyribonucleic acid, which transmits information from parent to offspring. A single molecule of DNA has thousands of genes. A chromosome is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division.

Chromosomes have two components:

• Chromatids: two copies of each chromosome
• Centromeres: protein discs that attach the chromatids together

Human cells have 23 sets of different chromosomes. The two copies of each chromosome are called homologous chromosomes, or homologues. An offspring receives one homologue from each parent. When a cell contains two homologues of each chromosome, it is termed diploid (2n). A haploid (n) cell contains only one homologue of each chromosome. The only haploid cells humans have are the sperm and eggs cells known as gametes.

A. To a different cell

B. To another part of the same cell

C. To a region right outside the cell

D. To an area with a high ion concentration

There are two major types of receptor molecules that respond to an intercellular chemical signal:

• Intracellular receptors: These receptors are located in either the cytoplasm or the nucleus of the cell. Signals diffuse across the cell membrane and bind to the receptor sites on intracellular receptors, of the same cell.
• Membrane-bound receptors: These receptors extend across the cell membrane, with their receptor sites on the outer surface of the cell membrane. They respond to intercellular chemical signals that are large, water-soluble molecules that do not diffuse across the cell membrane.

A. Urinary system

B. Digestive system

C. Muscular system

D. Cardiovascular system

The cardiovascular system is closely associated with hematopoiesis because it includes the heart and blood vessels, which are responsible for circulating blood throughout the body. Hematopoiesis, the process of blood cell formation, primarily occurs in the bone marrow, which is part of the skeletal system. However, the cardiovascular system plays a crucial role in transporting these blood cells to various parts of the body once they are produced in the bone marrow.

So, while the skeletal system provides the site for hematopoiesis, the cardiovascular system is responsible for distributing the blood cells, making it the most closely associated system in this context.