Sat 2 Biology Vocab

Front 1

Abiotic Factors

Back 1

Nonliving factors in an ecosystem. They include: temperature, water, sunlight, wind, rocks, and soil.

Front 2

Abscisic acid (ABA)

Back 2

Plant hormone that inhibits growth

Front 3

Accessory pigments

Back 3

See antennae.

Front 4

Acoelomate

Back 4

An animal that has no true coelom. Flatworms are an example.

Front 5

Actin

Back 5

Protein that makes up the thin myofilaments in skeletal muscle

Front 6

Active Transport

Back 6

Movement of particles against a gradient, from low concentration to high concentration. This always requires the expenditure of energy

Front 7

Adventitious roots

Back 7

Roots that arise above ground; examples are aerial roots and prop roots

Front 8

Agonistic behavior

Back 8

Agressive behavior

Front 9

Alcohol fermentation

Back 9

The process by which certain cells convert pyruvic acid or pyruvate from glycolysis into ethyl alcohol and carbon dioxide in the absence of oxygen.

Front 10

Allantois

Back 10

Extra embryonic membrane in bird's egg. It exchanges respiratory gases to and from the embryo

Front 11

Alleles

Back 11

Alternate forms of a gene. For example, there are two alleles for height in pea plants, tall and dwarf.

Front 12

Alveolus (alveoli)

Back 12

Microscopic air sacs in the lung where diffusion of the of the respiratory gases, oxygen and carbon dioxide occurs

Front 13

Amnion

Back 13

Membrane that encloses the embryo in protective amniotic fluid.

Front 14

Amylase

Back 14

Enzyme that digests starch.

Front 15

Analogous structures

Back 15

Structures, such as a bat's wing and a fly's wing, that have the same function but not the same underlying structure. The similarity is merely superficial and reflects adaptation to a similar environment. Analogous structures are not evidence of a common origin or common ancestry.

Front 16

Aneuploidy

Back 16

Any abnormal condition of the chromosomes.

Front 17

Angiosperms

Back 17

Anthophyta or flowering plants.

Front 18

Anion

Back 18

A negative ion.

Front 19

Antennae or accessory pigments

Back 19

Molecules that assist in photosynthesis by capturing and passing on photons of light to chlorophyll a and expanding the range of light that can be used to produce sugar. Examples are chlorophyll b and the carotenoids

Front 20

Anther

Back 20

Male part of flower where sperm (pollen) is produced by meiosis. Sits atop the filament.

Front 21

Antheridia

Back 21

Structures located on the tips of a gametophyte plant and that produce sperm

Front 22

Antibodies

Back 22

Immunoglobins. Part of the third line of defense, the specific immune response. Each antibody molecule is a Y-shaped molecule consisting of four polypeptide chains

Front 23

Anticodon

Back 23

The three-nucleotide sequence associated with tRNA

Front 24

Antigens

Back 24

Anything that triggers an antibody response.

Front 25

Apoptosis

Back 25

Programmed cell death.

Front 26

Archaeopteryx

Back 26

An intermediate fossil that shows both reptile and bird characterisitcs

Front 27

Archegonia

Back 27

Structures located on the tips of a gametophyte plant and that produce eggs.

Front 28

Associative learning

Back 28

One type of learning in which one stimulus becomes linked to another through experience

Front 29

ATP or adenosine triphosphate

Back 29

Special high-energy molecule that stores energy for immediate use in the cell.

Front 30

ATP synthase

Back 30

Structure in the membranes of mitochondria and chloroplasts where ATP is formed

Front 31

Autonomic nervous system

Back 31

Part of the nervous system that controls automatic functions, such as heart and breathing rate

Front 32

Autosomes

Back 32

Chromosomes other than the sex chromosomes. Humans normally have 44 in each body cell.

Front 33

Autotrophs

Back 33

Organisms that make their own food.

Front 34

Auxins

Back 34

Growth hormones in plants that are responsible for phototropisms and apical dominance, the preferential growth of a plant upward (toward the sun) rather than laterally.

Front 35

Backcross

Back 35

Testcross. A technique to determine whether an individual plant or animal showing the dominant trait is homozygous dominant (BB) or heterozygous (Bb)

Front 36

Bacterial transformation

Back 36

The ability of bacteria to alter their genetic makeup by uptaking foreign DNA from another bacterial cell and incorporating it into their own. Discovered by the scientist named Griffith

Front 37

Base-pair substitution

Back 37

A mutation where one nucleotide is substituted for a correct one in the DNA strand.

Front 38

Bicarbonate ion

Back 38

The most important buffer in human blood. It is responsible for keeping the pH of the blood at 7.4

Front 39

Bile

Back 39

Chemical produced in the liver and released from the gallbladder that emulsifies fats. It is not an enzyme.

Front 40

Binomial nomenclature

Back 40

System of taxonomy that we use today, developed by Carl von Linne. In this system, every organism has a two-part name, like Homo Sapiens.

Front 41

Biological magnification

Back 41

Organisms at higher trophic levels have a greater concentration of accumulated toxins stored in their bodies than those at lower trophic levels.

Front 42

Biosphere

Back 42

The global ecosystem

Front 43

Biotechnology

Back 43

The branch of science that uses recombinant DNA techniques for practical purposes, also called genetic engineering.

Front 44

Biotic factor

Back 44

Includes all the organisms with which an organism might react in an ecosystem.

Front 45

Biotic potential

Back 45

The maximum rate at which a population could increase under ideal conditions.

Front 46

Bottleneck effect

Back 46

Natural disasters such as fire, earthquake, and flood reduce the size of a population nonselectively, resulting in a loss of genetic variation. The resulting population is much smaller and not representative of the original one. Certain alleles may be under- or overrepresented compared with the original population.

Front 47

Budding

Back 47

Splitting off of new individuals from existing ones. How reproduction occurs in hydra.

Front 48

Buffers

Back 48

Chemicals that resist a change in pH.

Front 49

C-4 photosynthesis

Back 49

Modification for dry environments. C-4 plants exhibit modified anatomy and biochemical pathways, which enable them to minimize excessive water loss and maximize sugar production.

Front 50

Calvin Cycle

Back 50

Cyclical process that produces sugar. It occurs during the light-independent reactions.

Front 51

Carbon fixation

Back 51

Incorporation of carbon dioxide into a sugar. It occurs during the cyclical process called the Calvin Cycle.

Front 52

Cardiac sphincter

Back 52

Band of muscle at the top of the stomach that keeps acidified food in the stomach from backing up into the esophagus and burning it.

Front 53

Carotenoids

Back 53

Photosynthetic antennae pigments. They are orange and yellow.

Front 54

Carpel

Back 54

Female part of the flower, produce the female gametophytes, ova. Each carpel consists of an ovary, stigma, and style. Also called the pistil.

Front 55

Carrying Capacity (K)

Back 55

A limit to the number of individuals that can occupy one area at a particular time.

Front 56

Cation

Back 56

A positive ion.

Front 57

Centrioles

Back 57

Responsible for division of the cytoplasm in animal cells; they are not present in plant cells. They consist of 9 triplets of microtubules arranged in a circle

Front 58

Centromere

Back 58

Specialized region of a chromosome that holds two sister chromatids together.

Front 59

Centrosome

Back 59

Consist of two centrioles at right angles to each other. Important during cell division in animal cells.

Front 60

Chemiosmosis

Back 60

This is how ATP is produced during oxidative phosphorylation. Protons only flow through the special ATP synthase channels and transfer energy to molecules of ATP.

Front 61

Chitin

Back 61

A polysaccharide that makes up the exoskeleton of insects and the cell walls of fungi.

Front 62

Chloroplasts

Back 62

Type of the plastid that carries out photosynthesis.

Front 63

Chorion

Back 63

Membrane that lies under the shell of an egg and allows for diffusion of respiratory gases between the outside environment and the inside of the shell

Front 64

Chromatin Network

Back 64

DNA in the nucleus that is wrapped with special proteins called histones into a visible network

Front 65

Chromoplasts

Back 65

Type of plastid that stores pigments that are responsible for the bright colors in fruit and flowers

Front 66

Classical conditioning

Back 66

Type of associative learning. Pavlov trained dogs to associate the sound of a bell with food. The result of this conditioning was that dogs would salivate upon merely hearing the sound of the bell even though no food was present.

Front 67

Cleavage

Back 67

Rapid mitotic cell division of the zygote that begins immediately after fertilization

Front 68

Cnidocytes

Back 68

Cells that house the stingers in cnidarians

Front 69

Codominance

Back 69

An inheritance pattern where both traits show at once. In humans, a person who has 2 different genes for blood type, A and B, has type AB blood.

Front 70

Codon

Back 70

The three-nucleotide sequence associated with mRNA.

Front 71

Coelomate

Back 71

An animal that has a true coelom, or body cavity. All chordates are coelomates.

Front 72

Coenzymes

Back 72

Vitamins that assist in the normal functioning of enzymes

Front 73

Coevolution

Back 73

The mutual evolutionary set of adaptations of two interacting species.

Front 74

Cofactors

Back 74

Minerals that assist in the normal functioning of enzymes.

Front 75

Cohesion tension

Back 75

The attraction of like molecules to stick together. Water molecules tend to stick together because they exhibit strong cohesion tension.

Front 76

Collenchyma cells

Back 76

Plant cells that have unevenly thickened cell walls but lack secondary cell walls. The strings of celery consist of collenchyma cells.

Front 77

Colon

Back 77

Another name for large intestine.

Front 78

Commensalism

Back 78

Symbiotic relationship in which one organism benefits and one is not affected by the other organism (+/0)

Front 79

Community

Back 79

Consists of all the organisms living in one area.

Front 80

Companion cells

Back 80

Make up phloem vessels, along with sieve tube elements.

Front 81

Conjugation

Back 81

A primitive form of sexual reproduction where individuals exchange genetic material

Front 82

Continental Drift

Back 82

The theory that states that the continents are floating and moving very slowly. Over millions of years, seven separate continents formed from on original continent, Pangea.

Front 83

Contractile vacuole

Back 83

Structure found in freshwater protista, like paramecia and amoeba, that pumps out excess water that diffuses inward because the organisms live in an environment that is hypotonic.

Front 84

Convergent evolution

Back 84

Type of evolution where unrelated species occupying the same environment and subjected to similar selective pressures show similar adaptations. The classic example is the whale (a mammal) and the fish

Front 85

Cortex

Back 85

Specialized region in a plant root or stem for storage and support.

Front 86

Cotyledon

Back 86

Food for the growing embryo in a dicot seed. The cells that make up the cotyledon are triploid (3n)

Front 87

Covalent bonds

Back 87

Bonds formed between atoms where electrons are shared.

Front 88

Crassulacean acid metabolism or CAM

Back 88

A form of photosynthesis that is an adaptation for dry conditions. These plants keep their stomates closed during the day and open at night, the reverse of how most plants behave.

Front 89

Cristae

Back 89

Series of inner membranes in mitochondria where cell respiration occurs.

Front 90

Crop

Back 90

Structure in birds, insects, and earthworms, among others, for temporary storage of food.

Front 91

Crossing-over

Back 91

A normal process in which homologous chromatids exchange genetic material. Crossover is important because it increases variation in the gametes.

Front 92

Cutin

Back 92

Waxy coating on the leaves that helps prevent excess water loss from the plant

Front 93

Cyclosis

Back 93

Movement of cytoplasm around the cell

Front 94

Cystic fibrosis

Back 94

The most common lethal genetic disease in the United States, 1 out of 25 Caucasians is carrier. Characterized by build-up of extracellular fluid in the lungs and digestive tract.

Front 95

Cytochromes

Back 95

Proteins that play a key role in electron transport chains in mitochondria and chloroplasts

Front 96

Cytokinesis

Back 96

Division of the cytoplasm. In animal cells, a cleavage furrow forms down the middle of the cell as the cytoplasm pinches inward and the two daughter cells separate from each other. In plant cells, a cell plate forms down the middle of the cell.

Front 97

Cytokinins

Back 97

Plant hormones that stimulate cell division and cytokinesis.

Front 98

Cytoplasm

Back 98

The entire region between the nucleus and plasma membrane

Front 99

Cytosol

Back 99

Semiliquid portion of the cytoplasm.

Front 100

Decomposer

Back 100

Organisms that play a vital role in the ecosystem and that recycle dead organic matter. Examples are bacteria and fungi

Front 101

Dehydration synthesis

Back 101

Also known as synthesis. Process by which molecules are bonded together to form a larger molecule with the removal of water.

Front 102

Deletion

Back 102

A mutation where a piece of gene, or chromosome is lost.

Front 103

Denature

Back 103

Characteristic of proteins; a change in shape that stops the proteins from functioning.

Front 104

Deoxyribonucleic acid or DNA

Back 104

The heritable material, passed from parent to offspring

Front 105

Diastole

Back 105

Relaxation of the ventricles of the heart. Normal diastolic pressure is 120 mm Hg.

Front 106

Dicotyledon

Back 106

Plant whose seed easily breaks in two.

Front 107

Diffusion

Back 107

The flow of molecules from a higher concentration to a lower concentration. There are two types: simple and facilitated.

Front 108

Digestion

Back 108

Enzymatic breakdown, hydrolysis, of food so it is small enough to be assimilated into the body.

Front 109

Dipeptide

Back 109

A molecule consisting of two amino acids

Front 110

Directional selection

Back 110

Changing environmental conditions give rise to this type of natural selection. One phenotype replaces another in the gene pool.

Front 111

Disruptive selection

Back 111

This type of natural selection increases the numbers of extreme types in a population at the expense of intermediate forms.

Front 112

Divergent evolution

Back 112

Occurs when a population becomes isolated (for any reason) from the rest of the species and becomes exposed to new selective pressures, causing it to evolve into a new species. Homologous structures are evidence of divergent evolution.

Front 113

DNA polymerase

Back 113

The enzyme that catalyzes the elongation of the new DNA strands during replication.

Front 114

Domain

Back 114

In the newest system of classification, all organisms are classified in one of the three domains, which are further divided into kingdom, phylum, class, order, family, genus, and species

Front 115

Duodenum

Back 115

The first 10 inches of small intestine. Where all digestion is completed.

Front 116

Ecosystem

Back 116

Includes all the organisms in a given area as well as the abiotic (nonliving) factors with which they interact

Front 117

Ectoderm

Back 117

The outermost layer of an embryo, which develops into skin and nervous system

Front 118

Ectotherm

Back 118

The outermost layer of an embryo, which develops into skin and nervous system.

Front 119

Egestion

Back 119

Removal of metabolic waste.

Front 120

Electron transport chain (ETC)

Back 120

Consists of a series of molecules within the cristae membrane of mitochondria that provides the energy to phosphorylate ADP into ATP during oxidative phosphorylation.

Front 121

Endoderm

Back 121

The innermost layer of an embryo, which develops into the viscera or the digestive system.

Front 122

Endoplasmic Reticulum

Back 122

System of transport channels within the cytoplasm of a eukaryotic cell.

Front 123

Endosperm

Back 123

Food for the growing embyro in a monocot seed. The cells that make up the endosperm are triploid (3n)

Front 124

Endotherm

Back 124

An animal that uses metabolic energy to maintain constant body temperature; warm-blooded

Front 125

Energy of activation

Back 125

The amount of energy required to start a reaction.

Front 126

Eohippus

Back 126

A transition fossil that demonstrates that the ancient horse is an ancestor of the modern horse, Equus.

Front 127

Epicotyl

Back 127

Part of the embryo in a seed that becomes the upper part of the stem and leaves.

Front 128

Epididymis

Back 128

Part of testes where sperm become motile

Front 129

Epiglottis

Back 129

Flap of cartilage in the back of the throat that directs food to the esophagus

Front 130

Erythrocytes

Back 130

Red blood cells.

Front 131

Ethylene

Back 131

Gaseous plant hormone that promotes fruit ripening

Front 132

Eukaryotes

Back 132

Cells that contain internal membranes. The opposite of prokaryotic cells.

Front 133

Excited state

Back 133

When an atom absorbs energy, its electrons move to a higher energy level.

Front 134

Excretion

Back 134

Removal of metabolic wastes

Front 135

Exocytosis

Back 135

The release of substances from a cell

Front 136

Exons

Back 136

Expressed sequences of DNA. DNA that codes for particular polypeptides.

Front 137

Extremophiles

Back 137

Organisms that live in extreme environments, like methanogens, halophiles, and thermophiles. These organisms make pu the domain Archaea.

Front 138

FAD or flavin adenine dinucleotide

Back 138

Coenzyme that shuttles protons and electrons from glycolysis and the Krebs cycle to the electron transport chain.

Front 139

Fermentation

Back 139

Anaerobic phase of cell respiration.

Front 140

Filament.

Back 140

Threadlike structure that holds up the anther in the male part of a flower.

Front 141

Filtration

Back 141

Process that occurs in the nephron where nutrients and wastes diffuse from the glomerulus into bowman's capsule

Front 142

Final transcript

Back 142

The strand of mRNA that is sent to the ribosome after processing. The final transcript is much shorter than the initial transcript.

Front 143

Fission

Back 143

Division of an organism into two new cells. Reproduction in protists.

Front 144

Fixed action pattern

Back 144

Innate, highly stereotypical behavior, which once begun is continued to completion, no matter how useless or silly looking. FAPs are initiated by external stimuli called sign stimuli.

Front 145

Food Chain

Back 145

Pathway along which food is transferred from one trophic or feeding level to another.

Front 146

Founder effect

Back 146

A small population, which is not representative of the larger population, breaks away from the larger one to colonize a new area. Rare alleles may be under- or overrepresented.

Front 147

Fragmentation

Back 147

A single parent organism breaks into parts that regenerate into new individuals. Reproduction in sponges, planaria, and sea stars.

Front 148

Frameshift

Back 148

An error in the DNA in which the entire reading frame is altered. This can be caused by an insertion or deletion.

Front 149

G3P, glyceraldehyde-3-phosphate, or PGAL

Back 149

First sugar produced by photosynthesis

Front 150

Gametangia

Back 150

In primitive plants, a protective jacket of cells in which gametes and zygotes develop and which prevents drying out.

Front 151

Gametophyte

Back 151

Haploid (n) generation of a plant.

Front 152

Gastrin

Back 152

Digestive hormone that stimulates sustained secretion of gastric juice from the stomach.

Front 153

Gastrovascular cavity

Back 153

Gastrocoel, primitive digestive cavity in hydra

Front 154

Gastrulation

Back 154

The process by which a blastula develops into a gastrula with the formation of three embryonic layers

Front 155

Gel electrophoresis

Back 155

Process that separates large molecules of DNA on the basis of their rate of movement through an agarose gel in an electric field.

Front 156

Gene flow

Back 156

Movement of alleles into or out of a population

Front 157

Genetic drift

Back 157

Change in the gene pool due to chance. Two examples are the bottleneck effect and the founder effect.

Front 158

Genetic engineering

Back 158

Branch of science that uses recombinant DNA techniques for practical purposes, also called biotechnology.

Front 159

Genome

Back 159

An organism's genetic material. The human genome consists of 3 billion base pairs of DNA and about 30,000 genes.

Front 160

Genotype

Back 160

The kind of genes an organism has.

Front 161

Geographic isolation

Back 161

Separation by mountain ranges, canyons, rivers, lakes, or glaciers, may cause significant location.

Front 162

Gibberellins

Back 162

Plant hormones that promote stem and leaf elongation.

Front 163

Gizzard

Back 163

Structure in birds, insects, and earthworms where mechanical digestion of food occurs.

Front 164

Global warming

Back 164

Increase i average temperature of Earth. It is due to the greenhouse effect.

Front 165

Glucagon

Back 165

Hormone released by the pancreas that raises blood sugar

Front 166

Glycerol

Back 166

Combines with fatty acids to make lipids.

Front 167

Glycolysis

Back 167

The anaerobic phase of aerobic respiration. One molecule of glucose breaks apart into two molecules of pyruvate.

Front 168

Golgi apparatus

Back 168

Cell organelle that packages and secretes substances for the cell.

Front 169

Gradualism

Back 169

The theory that organisms descended from a common ancestor gradually, over a long period of time, in a linear or branching fashion.

Front 170

Grana

Back 170

Membranes within chloroplasts that consist of thylakoid membranes and are the sites of the light-dependent reactions of photosynthesis.

Front 171

Greenhouse effect

Back 171

Carbon dioxide and water vapor in the air absorb much of the infrared radiation reflecting off Earth, causing the average temperature on Earth to rise.

Front 172

Gross primary productivity

Back 172

Amount of energy converted to chemical energy by photosynthesis per unit time in an ecosystem

Front 173

Ground state

Back 173

Condition of an electron when it is not excited. It is in its lowest energy level.

Front 174

Guard cells

Back 174

Modified epithelium containing chloroplasts that control the opening and closing of the stomates by a change in shape.

Front 175

Gymnosperms

Back 175

Confers or cone-bearing trees

Front 176

Habituation

Back 176

One of the simplest forms of learning in which an animal comes to ignore a persistent stimulus so it can go about its business.

Front 177

Half-Life

Back 177

Amount of time it takes for a radioactive isotope to decay to half its mass.

Front 178

Halophiles

Back 178

Organisms that thrive in environments with high salt concentrations like Utah's Great Salk Lake.

Front 179

Haploid

Back 179

Having half the chromosome number.

Front 180

Heat of vaporization

Back 180

The amount of energy required to change a specified amount of liquid into a gas. Water has a high heat of vaporization.

Front 181

Heliobacter pylori

Back 181

Bacteria that is the cause of most ulcers.

Front 182

Hemocoels

Back 182

Sinuses. Cavities in the body of insects, like grasshoppers, for exchange of nutrients and wastes.

Front 183

Hemophilia

Back 183

An inherited disease caused by the absence of one or more proteins necessary for normal blood clotting.

Front 184

Hermaphrodites

Back 184

Organisms that contain both female and male sex organs.

Front 185

Heterotroph hypothesis

Back 185

Theory that the first cells on Earth were anaerobic, heterotrophic prokaryotes.

Front 186

Heterotrophs

Back 186

Organisms that must take in all their nutrients

Front 187

Histamine

Back 187

An important chemical in the immune system that triggers vasodilation (enlargement of blood vessels), which increases blood supply to an area. Histamine is also responsible for the symptoms of the common cold: sneezing, coughing, redness, itching and runny nose and eyes - all an attempt to rid the body of invaders

Front 188

Histones

Back 188

Special proteins that wrap around DNA, forming chromatin network.

Front 189

Homeostasis

Back 189

Internal stability

Front 190

Homeotherm

Back 190

Endotherm. Animals that maintain a consistent body temperature. Examples are birds, mammals, and some reptiles.

Front 191

Homologous structures

Back 191

The same internal bone structure, although the function of each varies. Examples of homologous structures are the wing of a bat, the lateral fin of a whale, and the human arm. If organisms have homologous structures, it means they have a common ancestor.

Front 192

Huntington's disease

Back 192

A degenerative inherited disease of the nervous system resulting in certain and early death. The gene that cause it is dominant, and onset is usually in middle age.

Front 193

Hydrogen bonding

Back 193

An intermolecular attraction between molecules that exert a strong pull on their electrons. This attraction keeps the two strands of a DNA molecule together.

Front 194

Hydrophillic

Back 194

Soluble in water. Hydrophilic substances are either polar or ionic.

Front 195

Hydrophobic

Back 195

Insoluble in water. Hydrophobic substances are nonpolar.

Front 196

Hypertonic

Back 196

Having greater concentration of solute than another solution.

Front 197

Hypocotyl

Back 197

Part of the embryo in a seed that becomes the lower part of the stem and the roots.

Front 198

Hypothalamus

Back 198

Major gland in the brain that is the bridge between the endocrine and nervous systems.

Front 199

Hypotonic

Back 199

Having less concentration of solute than another solution.

Front 200

Imprinting

Back 200

Learning that occurs during a sensitive or critical period in the early life of an individual and is irreversible for the length of that period.

Front 201

Incomplete dominance

Back 201

An inheritance pattern characterized by blending of traits. An example is crossing an animal with black fur with one with white fur, producing offspring with gray fur.

Front 202

Ingestion

Back 202

Intake of nutrients

Front 203

Initial transcript

Back 203

Strand of mRNA before it is processed. The initial transcript is much longer than the final transcript.

Front 204

Insertion

Back 204

A mutation where one nucleotide inserts itself into an existing strand. This mutation can cause a frameshift.

Front 205

Insulin

Back 205

Hormone released by the pancreas that lowers blood sugar

Front 206

Intermolecular attraction

Back 206

Attraction between molecules. One example is hydrogen bonding.

Front 207

Introns

Back 207

Intervening, noncoding sequences of DNA located between genes.

Front 208

Inversion

Back 208

A chromosomal fragment breaks off and reattaches to its original chromosome but in the reverse orientation.

Front 209

Ionic bonds

Back 209

Bonds between atoms that form by transferring electrons.

Front 210

Irritability

Back 210

Ability to respond to stimuli.

Front 211

Isotonic

Back 211

Solution containing equal concentrations of solute

Front 212

Junk

Back 212

Noncoding regions of DNA. Most of the human genome consists of noncoding regions.

Front 213

Karyotype

Back 213

Procedure that analyzes the size, shape, and number of chromosomes.

Front 214

Krebs cycle

Back 214

Also known as the citric acid cycle; the first stage of the aerobic phase of cellular respiration. It occurs in the inner matrix of mitochondria.

Front 215

Lacteal

Back 215

Structures within the villi that line the small intestine and that absorb fatty acids and glycerol into the lymphatic system.

Front 216

Lactic acid fermentation

Back 216

Occurs during strenuous exercise when the body cannot keep up with the increased demand for oxygen by skeletal muscles and pyruvic acid converts to lactic acid, which builds up in the muscle and causes fatigue and burning.

Front 217

Law of dominance

Back 217

Mendel's first law that sates that when two organisms, each homozygous (pure) for two opposing traits are crossed, the offspring will be hybrid but will exhibit only the dominant trait. The trait that remains hidden is the recessive trait.

Front 218

Law of independent assortment

Back 218

Best demonstrated by the dihybrid cross. A cross that is carried out between two individuals hybrid for two or more traits that are not on the same chromosome - the resulting phenotype ratio is 9:3:3:1

Front 219

Law of segregation

Back 219

During the formation of gametes, the traits carried on homologous chromosomes separate.

Front 220

Learning

Back 220

Sophisticated process in which the responses of the organism are modified as a result of experience.

Front 221

Leucoplast

Back 221

Type of plastid that stores starch.

Front 222

Leukocyte

Back 222

White blood cells.

Front 223

Light-dependent reactions

Back 223

Part of photosynthesis that requires light, produces ATP, and releases oxygen

Front 224

Light-independent reactions

Back 224

Part of photosynthesis that does not require light directly, only the products of the light-dependent reactions. Sugar (PGAL) is the product.

Front 225

Limiting factors

Back 225

Those factors that limit population growth. They are divided into two categories, density-dependent and density-independent factors.

Front 226

Lipid

Back 226

One type of organic molecule. It consists of one glycerol plus three fatty acids.

Front 227

Locomotion

Back 227

Moving from place to place.

Front 228

Lysosome

Back 228

Cell organelle that consists of digestive (hydrolytic) enzymes and is the principal site of intracellular digestion in the cell.

Front 229

Macroevolution

Back 229

Refers to speciation, the formation of an entirely new species.

Front 230

Malpighian tubule

Back 230

Structures in grasshoppers for removal of the nitrogenous waste uric acid.

Front 231

Malthus

Back 231

Published a treatise on population growth, disease, and famine in 1798 that influenced Darwin in the development of his theory of natural selection. Malthus stated that populations tend to grow exponentially, to overpopulate, and to exceed their resources.

Front 232

Medusa

Back 232

Upside-down-bowl-shaped body type

Front 233

Meiosis

Back 233

Type of cell division in sexually reproducing organism that produces haploid (n) gametes

Front 234

Menopause

Back 234

Cessation of the menstrual cycle.

Front 235

Meristem tissue

Back 235

Plant tissue that is always dividing. An example is cambium tissue.

Front 236

Mesoderm

Back 236

The middle layer of an embryo that develops into blood, bones, and muscle.

Front 237

Mesoglea

Back 237

The middle layer of a two-layered animal, like sponges or hydra, which holds the two layers together.

Front 238

Messenger RNA or mRNA

Back 238

Carries messages directly from DNA in then nucleus to the cytoplasm during protein synthesis.

Front 239

Metabolism

Back 239

The sum total of all the life functions.

Front 240

Methanogens

Back 240

Organisms that obtain energy in a unique way by producing methane from hydrogen.

Front 241

Microevolution

Back 241

Changes in one gene pool of a population over generations

Front 242

Microfilaments

Back 242

Made of the protein actin and help support the shape of the cell. They enable animal cells to form a cleavage furrow during cell division or the amoeba to move by sending out pseudopods.

Front 243

Microtubules

Back 243

Thick hollow tubes that make up the cilia, flagella, and spindle fibers.

Front 244

Middle lamella

Back 244

Layer of tissue between two cell walls of adjacent plant cells.

Front 245

Mitochondrion

Back 245

Cell organelle that produces ATP. Present in both plants and animals.

Front 246

Mitosis

Back 246

Type of cell division for growth and repair that produces two genetically identical daughter cells with the same chromosome number as the parent cell. Consists of four phases: prophase, metaphase, anaphase, and telophase.

Front 247

Molecule

Back 247

The name give tot wo or more atoms joined by a covalent bond.

Front 248

Monocotyledon

Back 248

Plant whose seed does not break into two parts. An example is corn.

Front 249

Monohybrid cross

Back 249

(Tt x Tt) A cross between two organisms that are each hybrid for one trait.

Front 250

Monotremes

Back 250

Egg-laying mammals, like the duck-billed platypus and the spiny anteater, which derive nutrients from a shelled egg.

Front 251

Multiple alleles

Back 251

When there are more than two allelic forms of a gene. For example, in humans, there are more than 2 alleles for blood type. There are A, B, and O.

Front 252

Mutation

Back 252

Any change in a gene or chromosome.

Front 253

Mutualism

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Symbiotic relationship where both organisms benefit (+/+). An example is the bacteria that live in the human intestine and that produce vitamins.

Front 254

Mycorrhizae

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Symbiotic structures consisting of the plant's roots intermingled with the hyphae (filaments) of a fungus, which greatly increase the quantity of nutrients that a plant can absorb.

Front 255

Myosin

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Myofilaments that make up the thick filaments in skeletal muscle.

Front 256

NAD or nicotinamide adenine dinucleotide

Back 256

Coenzyme that shuttles protons or electrons from glycolysis and the Krebs cycle to the electron transport chain.

Front 257

Nematocysts

Back 257

Stingers found in cnidocytes of cnidarians.

Front 258

Nephridia

Back 258

Structure in earthworms for excretion of the nitrogen waste urea.

Front 259

Net primary productivity

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Gross primary productivity minus the energy used by the primary producers for respiration

Front 260

Nondisjunction

Back 260

An error that sometimes happens during meiosis in which homologous chromosomes fail to separate as they should.

Front 261

Notochord

Back 261

A rod that extends the length of the body and serves as a flexible axis. This characteristic of all chordates.

Front 262

Nucleolus

Back 262

Where components of ribosomes are synthesized. This is a prominent region within the nucleus of a cell that is not dividing.

Front 263

Objective lens

Back 263

The lens on a light microscope that is closes to the stage.

Front 264

Ocular lends

Back 264

Eyepiece of a microscope.

Front 265

Omnivores

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Animals that normally eat both meat and vegetables in their diet.

Front 266

Oogenesis

Back 266

Formation of ova by meiotic cell division.

Front 267

Operant conditioning

Back 267

Trial and error learning.

Front 268

Organogenesis

Back 268

Process by which cells continue to differentiate, producing organs from the three embryonic germ layers.

Front 269

Origins of replication

Back 269

Special sites where replication begins in eukaryotic cells.

Front 270

Osmosis

Back 270

Diffusion of water across a membrane.

Front 271

Ovary

Back 271

Swollen part of pistil of flower that contains the ovule, whee one or more ova are produced.

Front 272

Oviduct or fallopian tube

Back 272

Where fertilization occurs. After ovulation the egg moves through the oviduct to the uterus.

Front 273

Ovule

Back 273

The structure within the ovary of a flower where the ova (female gametophyte) are produced.

Front 274

Oxidation

Back 274

Loss of electrons

Front 275

Oxidative phosphorylation

Back 275

Process that provides most of the energy (ATP) produced during cell respiration.

Front 276

Oxytocin

Back 276

Hormone secreted by the posterior pituitary that stimulates the uterus and causes contractions during labor.

Front 277

Pangaea

Back 277

Single supercontinent on ancient Earth that slowly separated into seven separate continents over the course of 150 million years. This is evidence of the theory of continental drift.

Front 278

Parallel evolution

Back 278

Two related species that have made similar evolutionary adaptations after their divergence from a common ancestor.

Front 279

Parasitism

Back 279

Symbiotic relationship (+/-) where one organism, the parasite, benefits while the host is harmed.

Front 280

Parenchyma cells

Back 280

Traditional-looking plant cell. Have a primary cell wall that is thin and flexible but lack a secondary cell wall.

Front 281

Parthenogenesis

Back 281

The development of an egg without fertilization. The resulting adult is haploid.

Front 282

Pathogen

Back 282

Organism that causes disease.

Front 283

Pedigree

Back 283

Family tree that indicates the phenotype of one trait being studied for every member of a family.

Front 284

Peptidases

Back 284

Enzymes that break down proteins into amino acids.

Front 285

Phagocytosis

Back 285

Cellular process of engulfing food and encapsulating it in a vacuole.

Front 286

Pharynx

Back 286

Throat

Front 287

Phenotype

Back 287

The traits an organism expresses.

Front 288

Phenylketonuria

Back 288

An inherited disease characterized by the inability to break down the amino acid phenylalanine. Requires elimination of phenylalanine from diet, otherwise serious mental retardation will result.

Front 289

Photolysis

Back 289

The process that occurs during the light-dependent reactions in which water is ripped apart to provide electrons to replace those lost by chlorophyll a. Oxygen is released.

Front 290

Photosynthetic pigments

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Chemicals that absorb light energy and use it to carry out photosynthesis. Examples are chlorophyll a, chlorophyll b, carotenoids, and phycobilins.

Front 291

Phycobilins

Back 291

A photosynthetic pigment.

Front 292

Pinocytosis

Back 292

Cellular process by which cells take in large dissolved molecules, referred to as cell drinking

Front 293

Pioneer organisms

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The first to colonize a barren environment in primary ecological succession.