Living Environment

Osmosis is the specific term for the diffusion of water across a semipermeable membrane from an area of high concentration to an area of low concentration without energy input.

Diffusion is the passive movement of molecules from a region of higher concentration to a region of lower concentration until equilibrium is reached.

Peptic ulcers are sores that develop on the lining of the stomach, often caused by the bacterium Helicobacter pylori.

Prokaryotic cells, such as bacteria, are defined by the absence of a membrane-bound nucleus and other membrane-bound organelles.

Centrioles are organelles involved in cell division and are typically found in animal cells but are absent in most plant cells.

An antigen is any substance, such as a bacterium, that the body recognizes as foreign and triggers an immune response.

Antibodies are proteins produced by the immune system in response to specific antigens to help neutralize or destroy them.

In an energy pyramid, the arrows represent the direction of energy transfer from one trophic level to the next.

Decomposers break down dead organic matter, returning nutrients and energy back into the ecosystem and soil.

The sun is the primary source of energy for almost all ecosystems on Earth, driving photosynthesis in producers.

Mitosis is the process of cell division that results in two genetically identical daughter cells, used for growth and tissue repair.

Meiosis is a specialized type of cell division that reduces the chromosome number by half to produce gametes (sperm and egg cells).

The mitochondria are known as the powerhouse of the cell because they are the site of cellular respiration, where ATP is generated.

Photosynthesis uses carbon dioxide and water as reactants to produce glucose and oxygen. Carbon monoxide is toxic and not a reactant, while glucose and oxygen are products.

Oxygen is released as a byproduct of photosynthesis. Water and sunlight are inputs, and carbon monoxide is not involved in this process.

Ribosomes are the cellular structures responsible for protein synthesis. The stomach and liver are organs, not organelles, and lysosomes are involved in waste breakdown.

DNA remains in the nucleus of eukaryotic cells. Instead, mRNA is transcribed from DNA and travels to the ribosome to direct protein synthesis.

The endoplasmic reticulum (ER) is a transport system within the cell, analogous to the circulatory system which transports materials throughout the body. The other systems have different primary functions.

Heterotrophs must consume other organisms for energy. Mushrooms are fungi that absorb nutrients from organic matter, whereas roses, corn, and apples are autotrophic plants.

A pulse is the rhythmic expansion and recoil of an artery due to the heart's contraction. Veins and capillaries do not exhibit this pressure wave.

The small intestine is the primary site for chemical digestion and nutrient absorption. The stomach begins digestion, but the small intestine completes it.

Proteins are polymers made of amino acid monomers. During digestion, enzymes break down these proteins into their constituent amino acids.

The stomach is a primary organ of the digestive tract, not an accessory organ. The liver, gallbladder, and pancreas are accessory organs that assist digestion.

Regular exercise helps strengthen the heart and improves blood vessel health, which helps lower blood pressure. High sodium intake and saturated fats generally increase hypertension risk.

Asthma is a chronic condition characterized by inflammation and constriction of the bronchioles. Bronchitis is inflammation of the bronchi, while emphysema involves damage to alveoli.

The epiglottis is a flap of cartilage that covers the trachea during swallowing to prevent food from entering the airway. The glottis is the opening itself.

The heart is composed of cardiac muscle, not smooth muscle. Smooth muscle is found in organs like the stomach and blood vessels.

Peristalsis is the wave-like muscle contraction that moves food through the digestive tract. It occurs in the esophagus, stomach, and intestines, but not the pharynx, which is involved in swallowing.

The primary function of the colon (large intestine) is to absorb water and electrolytes from indigestible food matter. It does not secrete bile or digest carbohydrates.

Gas exchange occurs in the lungs between the alveoli (air sacs) and the surrounding pulmonary capillaries. Oxygen enters the blood and carbon dioxide leaves it.

Pulmonary circulation refers to the loop between the heart and the lungs. Systemic circulation covers the rest of the body, and coronary circulation supplies the heart muscle.

The small intestine is the primary site for the absorption of nutrients into the bloodstream. While some absorption occurs in the stomach (like alcohol), the vast majority occurs in the small intestine.