Introduction to Biology Flashcards | Quizlet

What are the characteristics of life?

Different molecules than nonliving things; composed of cells; require energy; maintain homeostasis; respond to the environment; grow & reproduce; capable of evolving.

What does it mean for an organism to be capable of evolving?

Its population can undergo genetic changes over generations.

What is natural selection?

Individuals with favorable traits are more likely to survive and reproduce than individuals with unfavorable traits.

What is "survival of the fittest"?

Individuals with traits that make them better suited to their environment are more likely to survive and reproduce.

How does natural selection cause evolution?

Genetic changes that give organisms favorable traits become more common in a population.

What is bipedalism?

Walking on two legs; frees the hands to carry things.

What do opposable thumbs allow humans to do?

Have fine motor control.

Why is the human brain considered a defining feature?

Humans have a large brain relative to body size.

What language abilities are characteristic of humans?

The capacity for spoken and written language.

What is the order of biological organization from smallest to largest?

Atom/molecule → cell → tissue → organ → organ system.

What is the smallest unit of matter?

Atom/molecule.

What is the smallest unit of life?

Cell.

What is a tissue?

An association/group of cells.

What is an organ?

An association of tissues.

What is an organ system?

Two or more organs working together.

What is science?

Both a body of knowledge AND a process.

What is inductive reasoning?

Reasoning from specific observations to a general conclusion.

What is a hypothesis?

A proposed explanation that can be tested.

What is a testable prediction?

A specific outcome that can be tested based on a hypothesis.

What is deductive reasoning?

Applying a general idea to a specific case.

What happens during an experiment?

A hypothesis is tested through an experiment or observation.

Why is a large sample useful?

It provides more variety and can make results more representative.

What happens if the results don't support a hypothesis?

The hypothesis can be modified and tested again.

What is a scientific theory?

A hypothesis that has been repeatedly tested and supported over time.

What is an example of a scientific theory?

The Theory of Evolution.

What is the difference between correlation and causation?

Correlation means two things are associated; causation means one thing directly causes another.

What is critical thinking?

Evaluating information carefully and asking what evidence supports it.

What should you separate when critically thinking?

Facts from speculation.

What question should you ask when evaluating a claim?

"What is the evidence?"

What is an atom?

The smallest functional unit of matter.

What charge does a proton have?

Positive (+).

What charge does a neutron have?

No charge (0).

What charge does an electron have?

Negative (−).

Where are protons and neutrons located?

In the nucleus.

What is an isotope?

An atom with an abnormal number of neutrons.

What are radioisotopes?

Unstable isotopes that give off energy as they decay.

What is energy?

The capacity to do work.

What is potential energy?

Stored energy.

Why do atoms form bonds?

Bonds provide stability to molecules.

Why do electrons prefer to be paired?

Pairing provides greater stability.

What type of energy do electrons have?

Potential energy.

What is a covalent bond?

A strong bond in which atoms share electrons.

What is a polar molecule?

A molecule with an unequal distribution of charge, creating partial positive and negative regions.

What is an example of a polar molecule?

H₂O (water).

What is a nonpolar molecule?

A molecule in which charge is distributed more equally.

What is an ionic bond?

A bond between oppositely charged atoms/ions.

What is an example of an ionic bond?

Na⁺ + Cl⁻ → NaCl.

What is a hydrogen bond?

A weak attraction/bond between water molecules.

What six elements make up about 99% of body weight?

Carbon, hydrogen, oxygen, nitrogen, calcium, and phosphorus.

What is the abbreviation for the six major elements?

CHONCP.

What other elements are important in living organisms?

Sodium (Na), potassium (K), iron, and iodine.

Why is water important to life?

Life depends on water; it acts as a solvent and helps regulate body temperature.

Why is water polar?

It has partial charges in different parts of the molecule.

What type of bonds form between adjacent water molecules?

Hydrogen bonds.

What is one important biological function of water?

Water acts as a biological solvent and keeps ions in solution.

How does water help regulate body temperature?

Water can absorb and hold heat energy.

What does hydrophilic mean?

"Water-loving"; compounds that dissolve in water.

What are examples of hydrophilic substances?

Salt and sugar.

What does hydrophobic mean?

"Water-fearing"; compounds that do not dissolve in water.

What is an example of a hydrophobic substance?

Oil.

What does pH measure?

Hydrogen ion (H⁺) concentration.

What is an acid?

A hydrogen ion donor.

What is a base?

A hydrogen ion acceptor.

What does a low pH indicate?

Acidic.

What does a high pH indicate?

Basic/alkaline.

What is neutral pH?

7.

What is normal blood pH?

About 7.4.

What are buffers?

Substances that minimize changes in pH.

Why are buffers important?

They help maintain a stable pH in blood and cells.

Why can large changes in blood pH be deadly?

Proteins and other biological processes depend on a proper pH; major pH shifts can disrupt their function.

What are the five main categories of organic molecules discussed?

Carbohydrates, lipids, proteins, nucleic acids, and ATP.

Why is carbon important to living things?

Carbon is a major building block of living things.

How many covalent bonds can carbon form?

Four.

What types of bonds can carbon form?

Single and double covalent bonds.

What do organic molecules generally contain large amounts of?

Carbon and hydrogen.

What elements make up carbohydrates?

Carbon, hydrogen, and oxygen.

What are monosaccharides?

Single sugars; the building blocks of carbohydrates.

What are examples of monosaccharides?

Glucose, fructose, and ribose.

What is the formula for glucose?

C₆H₁₂O₆.

Why is glucose important?

It can be easily used as a source of fuel/energy.

What are disaccharides?

Two monosaccharides combined into a larger molecule.

What are carbohydrates used for?

Energy and structural support.

What are polysaccharides?

Long chains/branches made of many monosaccharides.

What is starch?

A plant polysaccharide used to store energy.

What is glycogen?

An animal polysaccharide that stores energy, especially in muscles and the liver.

What is cellulose?

An indigestible plant polysaccharide that provides structural support; a major component of fiber.

What do starch, glycogen, and cellulose have in common?

They are polysaccharides made of many glucose molecules.

What are lipids?

Organic molecules that are generally hydrophobic.

What are triglycerides?

Energy-storage molecules made of glycerol and three fatty acids.

Where is triglyceride energy stored in the body?

In adipose (fat) tissue.

What is a triglyceride made of?

One glycerol + three fatty acids.

What is a saturated fatty acid?

A fatty acid with only single bonds between carbon atoms.

What is the typical physical state of saturated fats at room temperature?

Solid.

What are common sources of saturated fats?

Animal fats.

What is an unsaturated fatty acid?

A fatty acid containing one or more double bonds.

Why do unsaturated fats have "kinks"?

Double bonds create bends in the fatty acid chain.

What is the typical physical state of unsaturated fats at room temperature?

Liquid.

What are common examples of unsaturated fats?

Plant oils.

What are trans fats?

Fats produced when vegetable oils are hydrogenated/saturated.

What effect can trans fats have on cholesterol?

They raise LDL cholesterol.