AP Bio: Topics 1-3

Basal metabolic rate

The minimum amount of energy the body uses while at rest to keep basic life processes working.

Scaling relationships

Relationships between an organism’s body size and characteristics such as its metabolic rate.

Interstitial fluid

Fluid that surrounds and bathes the cells of the body.

Internal environment

The conditions surrounding an organism’s cells.

External environment

Everything outside of an organism that can affect it.

Regulation

The process of controlling internal conditions so they stay within a suitable range.

Conformity

When an organism’s internal conditions change as the external environment changes.

Thermoregulation

The regulation of body temperature so it stays within a suitable range.

Homeotherm

An organism that maintains a relatively constant body temperature even when the outside temperature changes.

Thermoneutral zone

The range of environmental temperatures where an animal does not need to use extra energy to maintain its body temperature.

Poikilotherm / Ectotherm

An organism whose body temperature changes with the environment and that relies mainly on external sources of heat.

Nonshivering thermogenesis

Producing heat without shivering by increasing metabolic activity.

Brown adipose tissue (BAT)

Specialized fat tissue that produces heat by using stored energy.

Hibernation

A state of greatly reduced metabolism, body temperature, and activity that helps an animal survive cold conditions or a lack of food.

Homeostasis

The maintenance of relatively stable internal conditions despite changes in the internal or external environment.

Sensors / Receptors

Structures that detect changes in the internal or external environment.

Control centers / Control mechanisms

Structures that receive information from sensors and determine what response is needed.

Effectors

Structures, such as muscles or glands, that carry out the response.

Feedback

Information about a response that is used to control or adjust a process.

Negative feedback

A response that reverses or reduces the original change and helps maintain homeostasis.

Positive feedback

A response that increases or strengthens the original change.

Root

A plant organ that anchors the plant and absorbs water and minerals from the soil.

Shoot

The aboveground part of a plant, including stems, leaves, and buds.

Stem

Supports the plant and transports water, minerals, and sugars.

Leaves

Plant organs that carry out most photosynthesis and gas exchange.

Bud

An undeveloped shoot that can grow into leaves, stems, or flowers.

Lateral meristem

Tissue that produces secondary growth, making a plant wider or thicker.

Apical meristem

Tissue at the tips of roots and shoots that produces primary growth, making the plant longer.

Cell wall

A rigid structure outside the cell membrane that supports and protects plant cells.

Cellulose

A carbohydrate that makes up much of the plant cell wall and gives it strength.

Totipotency

The ability of a plant cell to develop into an entire plant.

Cotyledon

A seed leaf that provides nutrients to a developing plant embryo.

Shoot apical meristem

The meristem at the tip of a shoot that produces new stems and leaves.

Root apical meristem

The meristem at the tip of a root that produces new root cells and allows the root to grow longer.

Epidermis

The outer layer of cells that covers and protects a plant.

Cuticle

A waxy layer on the epidermis that helps prevent water loss.

Ground tissue

Plant tissue that performs functions such as photosynthesis, storage, and support.

Parenchyma

Living, relatively unspecialized cells that perform functions such as photosynthesis and storage.

Collenchyma

Living cells with unevenly thickened walls that provide flexible support.

Sclerenchyma

Cells with thick, rigid walls that provide strong support.

Xylem

Vascular tissue that transports water and minerals, mainly from the roots upward.

Vessel elements

Specialized xylem cells that form tubes for transporting water.

Phloem

Vascular tissue that transports sugars and other organic nutrients throughout the plant.

Sieve tube elements

Specialized phloem cells that form tubes for transporting sugars.

Companion cells

Cells that support and help sieve tube elements transport sugars.

Determinate growth

Growth that stops after a structure reaches a certain size.

Indeterminate growth

Growth that continues throughout a plant’s life.

Primary growth

Growth that increases the length of roots and shoots.

Secondary growth

Growth that increases the width or thickness of roots and stems.

Root cap

A structure that protects the root apical meristem as the root grows through soil.

Zone of cell elongation

The region of the root where newly produced cells grow longer, causing the root to extend.

Zone of cell maturation

The region where root cells finish developing and become specialized.

Taproot systems

Root systems with one large main root and smaller lateral roots.

Fibrous root systems

Root systems made up of many thin roots of similar size.

Vascular bundles

Groups of xylem and phloem that transport materials through a plant.

Blade

The broad, flat part of a leaf that captures light for photosynthesis.

Mesophyll

The internal leaf tissue where most photosynthesis occurs.

Petiole

The stalk that connects the leaf blade to the stem

Calorie

A unit of energy; the amount of energy needed to raise the temperature of 1 gram of water by 1°C.

Kilocalorie

1,000 calories; the unit commonly used to measure energy in food.

Joule

The standard scientific unit used to measure energy.

Essential nutrient

A nutrient that the body needs but cannot make in sufficient amounts, so it must come from the diet.

Standard amino acids

The 20 amino acids commonly used to build proteins.

Essential amino acids

Amino acids that the body cannot make and must obtain from food.

Essential fatty acids

Fatty acids that the body cannot make and must obtain from food.

Vitamin

An organic nutrient needed in small amounts for normal body functions.

Mineral

An inorganic nutrient needed by the body for normal functions.

Malnutrition

Poor nutrition caused by getting too little, too much, or an unbalanced amount of nutrients.

Deficiency disease

A disease or health problem caused by not getting enough of a particular nutrient.

Metabolic rate

The rate at which an organism uses energy.

Macromolecule

A large biological molecule, such as a protein, carbohydrate, lipid, or nucleic acid.

Polymer

A large molecule made of many smaller repeating units called monomers.

Monomer

A small molecule that can join with other monomers to form a polymer.

Lipids

A group of mostly water-insoluble molecules that includes fats, oils, phospholipids, and steroids.

Triglycerides

Lipids made of one glycerol molecule attached to three fatty acids; they are an important form of stored energy.

Saturated

A fatty acid containing only single bonds between its carbon atoms.

Unsaturated

A fatty acid containing one or more double bonds between its carbon atoms.

Phospholipids

Lipids made of glycerol, fatty acids, and a phosphate-containing group; they are major components of cell membranes.

Phospholipid bilayer

Two layers of phospholipids that form the basic structure of cell membranes, with hydrophilic heads facing water and hydrophobic tails facing inward.

Carbohydrate

A molecule made mainly of carbon, hydrogen, and oxygen that is used for energy, energy storage, and structure.

Monosaccharides

Single sugar molecules that are the simplest carbohydrates and the building blocks of larger carbohydrates.

Polysaccharides

Large carbohydrates made of many monosaccharides joined together.

Starch

A polysaccharide used by plants to store energy.

Glycogen

A polysaccharide used by animals to store glucose.

Cellulose

A structural polysaccharide that makes up much of the plant cell wall.

Nucleic acids

Macromolecules that store and transmit genetic information; DNA and RNA are nucleic acids.

Nucleotide

The monomer that makes up nucleic acids; it contains a sugar, phosphate group, and nitrogenous base.

Base

The nitrogen-containing part of a nucleotide that helps carry genetic information.

DNA

A nucleic acid that stores an organism’s genetic information.

DNA structure

DNA consists of two nucleotide strands twisted into a double helix. The sugar-phosphate backbones are on the outside, while the bases pair on the inside.

Pyrimidines

Smaller nitrogenous bases with one ring

Purines

Larger nitrogenous bases with two rings

Four bases of DNA

Adenine (A), thymine (T), cytosine (C), and guanine (G).

5′ to 3′ orientation

DNA strands have direction. One strand runs 5′ → 3′ and the opposite strand runs 3′ → 5′.

RNA

A nucleic acid that helps use genetic information to make proteins.

RNA structure

RNA is usually a single strand of nucleotides containing ribose sugar, phosphate groups, and nitrogenous bases.

Four bases of RNA

Adenine (A), uracil (U), cytosine (C), and guanine (G).

DNA replication

The process of copying DNA so that each new cell receives a complete set of genetic information.

Transcription

The process of using DNA information to make an RNA molecule.

Translation

The process of using the information in mRNA to build a protein.