Chapter_2_bio

What is matter?

Matter is any substance that occupies space and has mass.

How many elements are there, and how many occur naturally?

There are 118 elements, but only 98 occur naturally.

What are elements?

Elements are unique forms of matter with specific chemical and physical properties that cannot break down into smaller substances by ordinary chemical reactions.

What element's chemical symbol is 'C'?

Carbon.

What is an atom?

An atom is the smallest unit of matter that retains all of the element's chemical properties.

What are protons, and what charge do they carry?

Protons are positively charged particles found in the nucleus of an atom.

What is an isotope?

Isotopes are different forms of an element that have the same number of protons but a different number of neutrons.

What is the significance of carbon in macromolecules?

Carbon serves as the basic structural component, or 'backbone,' of macromolecules.

What is the octet rule?

The octet rule states that atoms are most stable when they hold eight electrons in their outermost shells.

What is a covalent bond?

A covalent bond is a type of strong bond formed when two atoms share electrons.

What defines a polar molecule?

A polar molecule has an unequal distribution of charges, leading to partially positive and negative regions.

What is a hydrogen bond?

A hydrogen bond is a weak bond between slightly positively charged hydrogen atoms and slightly negatively charged atoms in other molecules.

What role do buffers play in biological systems?

Buffers help maintain a stable pH by absorbing or releasing hydrogen or hydroxide ions.

What is the primary structure of water that allows it to support life?

Water's polarity and hydrogen bonding create unique properties essential for life.

In what form do macromolecules exist?

Macromolecules can exist as proteins, nucleic acids, carbohydrates, and lipids.

What is a carboxyl group's effect on molecules?

A carboxyl group ionizes to release hydrogen ions (H+), contributing to the hydrophilic nature of the molecule.

What are isomers?

Isomers are molecules that share the same chemical formula but differ in the arrangement of their atoms.

What defines the term 'hydrophilic'?

Hydrophilic describes molecules that interact well with water.

What role do the electron configuration and valence shell play in chemical reactivity?

The electron configuration determines an atom's capacity to bond with other atoms, influencing its reactivity.

How do plant roots utilize water's cohesive and adhesive properties?

Cohesion and adhesion help transport water from the roots to the leaves in plants.

What is a solvent?

A solvent is a substance that dissolves a solute, forming a solution.

What is solubility?

Solubility is the ability of a substance to dissolve in a solvent.

What is a solution?

A solution is a homogeneous mixture of two or more substances.

What is osmosis?

Osmosis is the diffusion of water across a selectively permeable membrane.

What is active transport?

Active transport is the movement of molecules across a membrane using energy, typically against their concentration gradient.

What is diffusion?

Diffusion is the passive movement of molecules from an area of higher concentration to an area of lower concentration.

What are gametes?

Gametes are reproductive cells (sperm and eggs) involved in sexual reproduction.

What is meiosis?

Meiosis is the process of cell division that reduces the chromosome number by half, producing gametes.

What is a genotype?

A genotype is the genetic constitution of an organism.

What is a phenotype?

A phenotype is the observable physical or biochemical characteristics of an organism.

What is a hypothesis?

A hypothesis is a proposed explanation for a phenomenon, which can be tested through experimentation.

What is a control group?

A control group is a baseline group in an experiment that does not receive the treatment being tested.

What is the scientific method?

The scientific method is a systematic approach to research that involves observation, hypothesis, experimentation, and conclusion.

What is cellular respiration?

Cellular respiration is the process through which cells convert glucose and oxygen into energy, carbon dioxide, and water.

What is photosynthesis?

Photosynthesis is the process by which green plants convert light energy into chemical energy in the form of glucose.

What is a polymer?

A polymer is a large molecule composed of repeating structural units called monomers.

What are lipids?

Lipids are hydrophobic organic molecules that include fats, oils, and phospholipids.

What is a catalyst?

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.

What is a chemical reaction?

A chemical reaction is the process that leads to the transformation of one set of chemical substances to another.

What is an enzyme's active site?

An enzyme's active site is the region where substrate molecules bind and undergo a chemical reaction.

What are vitamins?

Vitamins are organic compounds that are essential for normal growth and nutrition, typically required in small quantities.