Key Concepts for NYS Living Environment Regents Exam

Observation

What is seen or measured.

Inference

A conclusion based on observation or evidence.

Hypothesis

An untested prediction. A good hypothesis states both cause and effect ("If-then" statement).

Theory

A broad explanation of natural events that is supported by strong evidence.

Controlled Experiment

Compares the results of an experiment between two (or more) groups.

Experimental group

Group being tested or receiving treatment. (ex: new drug)

Control group

"Normal" group. Should be identical to experimental group in every way except one: it does not receive the treatment (i.e.: no drug, or given the original drug or a placebo).

Placebo

A sugar pill or other "fake" treatment given to the control group so subjects do not know which group they are in.

Independent Variable

Variable that is being tested (ex: new drug). In a graph the independent variable is always plotted on the X axis.

Dependent Variable

Variable that is measured at the end of an experiment; the results (ex: does patient get better?). The dependent variable is always plotted on the Y axis.

Homeostasis

All living things must maintain homeostasis.

Metabolism

All life processes make up an organism's metabolism.

Nutrition

Autotrophs make their own food, while heterotrophs eat other organisms.

Photosynthesis

Carried out by plants, alga and blue-green bacteria (autotrophs). It takes the radiant energy of the sun and puts it in the bonds of sugar molecules.

Respiration

Organisms get energy by breaking the bonds of sugar molecules.

Aerobic respiration

Requires oxygen, and yields more ATP (energy) for a molecule of sugar than anaerobic (no oxygen) respiration.

Anaerobic respiration

When humans are forced to get energy from anaerobic respiration, we produce lactic acid that damages muscles ("the burn" you feel during exercise).

Diffusion

Movement of molecules from high concentrations to low concentrations. Requires no energy (passive transport).

Active Transport

Requires the use of energy, usually moving molecules from a low concentration to a high concentration (against the flow of diffusion).

Osmosis

The diffusion of water into or out of the cell.

Stimulus

A change in the environment that you respond to.

Neuron

A nerve cell.

Impulse

The electrical signal carried by the nerves.

Neurotransmitters

Chemicals that help carry the impulse.

Hormone

A chemical signal secreted by different glands in the body.

Examples of hormones

Insulin, adrenaline, testosterone and estrogen.

Receptor molecules

Proteins on the surface of the cell membrane that receive signals from the nervous and endocrine system.

Common elements in living things

Carbon, Hydrogen, Oxygen and Nitrogen (CHON).

Organic Compounds

Compounds that have Carbon AND Hydrogen (ex: C6H12O6 is organic, H2O, CO2, and NO3 are not).

Carbohydrates

Sugars and starches made from simple sugars (like glucose) that supply energy.

Lipids

Molecules that store energy and include fats, oils and waxes, made from fatty acids and glycerol.

Proteins

Molecules made from amino acids that make hormones and many body and cell structures.

Shape of proteins

Determines what proteins can do.

Jobs of proteins

1) Make enzymes 2) Make receptor molecules on the cell membrane 3) Make antibodies 4) Make hormones.

Enzymes

Catalysts that affect the rates of chemical reactions.

Lock and key model

One type of enzyme fits one type of molecule; changing its shape will prevent it from working.

High temperatures effect on proteins

Very high temperatures cause proteins and enzymes to lose their shape, making them non-functional.

pH scale

Measures the strengths of acids and bases; a low pH (0-6.9) is an acid, a high pH (7.1-14) is a base, and 7 is neutral.

Cells

The basic unit of life; all living things (except viruses) are made of cells.

Cell theory

All living things are made of cells.

Differences between plant and animal cells

Must be known.

Organelles

Cell membrane, cell wall, nucleus, chloroplast, cytoplasm, ribosome, vacuole, mitochondria.

Cell membrane

Made of lipids and proteins, showing selective permeability.

Selective permeability

Only some molecules can pass through the cell membrane, typically small molecules like water and oxygen.

Cell wall

Mostly for protection; all cells have a cell membrane.

Classification

Organisms are classified mostly by evolutionary history.

Kingdoms

Large groups of related organisms (fungi, bacteria, protists, animals, plants).

Species

A group of organisms that can successfully reproduce amongst its members.

Scientific name

Made up of an organism's Genus and species.

Tissues

Groups of cells specialized to do certain jobs.

Specialization or differentiation

Occurs because only some genes in the nucleus of a cell are 'turned on'.

Organs

Formed when tissues work together.

Organ systems

Formed when organs work together.

Digestive System

The digestive system is a one way passage through the body that includes the mouth, stomach and intestines.

Peristalsis

Food is moved through the digestive system by muscular contractions.

Mechanical and Chemical Breakdown

Food is broken down mechanically and chemically.

Solid Waste Elimination

Undigested food is eliminated as solid waste. This is not excretion.

Transport/Circulatory System

Moves material (water, nutrients, hormones, wastes) through the body.

Red Blood Cells

Carry oxygen.

White Blood Cells

Fight disease.

Plasma

The fluid of the blood that transports everything except oxygen.

Platelets

Clot the blood.

Immune System

The job of the immune system is to protect the body against pathogens.

Pathogens

Types of pathogens include viruses, bacteria, and parasites.

Antigens

Cause an immune response.

Antibodies

Proteins made by white blood cells to attack antigens.

Blood Type O

Universal donor.

Blood Type AB

Universal acceptor.

Vaccine

An injection of a dead or weakened pathogen that causes the body to make antibodies against that pathogen.

Antibiotics

Drugs used to stop infections by bacteria; they will not work against viruses.

Physical Respiration

Breathing provides oxygen needed for chemical respiration.

Diaphragm

The muscle that allows breathing to occur.

Alveoli

Very important because it is here that the oxygen enters the blood and CO2 leaves.

Excretory System

Removes metabolic waste from your body.

Kidneys

Filter waste from blood and reabsorb nutrients.

Liver

Filters toxins and dead red blood cells from the blood.

Nervous System

Regulates your body along with the endocrine system.

Spinal Cord

Controls reflexes and brings impulses from the nerves to the brain.

Pancreas

Makes insulin and glucagon which control blood sugar.

Viruses

Examples include AIDS, cold, flu, chicken pox.

Bacteria

Examples include strep throat, food poisoning, syphilis.

Fungus

Examples include athlete's foot, ringworm.

Parasites

Examples include tapeworm, leeches.

Genetic disorders

Examples include Down's Syndrome, sickle cell, cystic fibrosis.

Environmental toxins

Examples include lead poisoning, radiation.

Poor nutrition

Examples include Scurvy, goiter.

Organ malfunction

Examples include heart attack, diabetes.

High risk behavior

Examples include smoking, drug use, exposure to sun.

Asexual reproduction

Advantages include faster and easier reproduction; disadvantage is no variety.

Sexual reproduction

Advantage is variety; disadvantage is more time, effort, and risk.

Mitosis

Asexual reproduction process where one division results in two identical diploid (2n) cells.

Meiosis

Sexual reproduction process where one cell divides twice to make four different haploid (n) cells.

Gametes

In humans, meiosis produces 4 sperm cells or 1 egg and three polar bodies.

Fertilization

Occurs in the fallopian tube; a fertilized egg is called a zygote.

Fetus development

Occurs in the uterus; cells divide without becoming larger (cleavage) and begin to differentiate.

Chromosomes in humans

Humans have 46 chromosomes, or 23 homologous pairs.

Alleles

Chromosome pairs carry alleles for the same trait; we have two alleles for each gene.

Gene expression

While genes determine traits, the environment can affect their expression.

DNA

Made of 4 bases: ATCG; a three-letter codon represents a specific amino acid.

Base pairs

A-T, C-G (in RNA, A-U and C-G).