Biology Sat II Vocabulary Flashcards
Abscisic Acid
Plant hormone that conserves water
Accessory Pigments
Molecules that assist in photosynthesis by capturing photons and transferring them to chlorophyll a, including chlorophyll b and carotenoids.
Acoelomates
Animals with no coelom:
Pseudocoelomates
Animals with a false coelom:
Coelomates
Animals with a coelom:
Actin
Protein found in muscle and myofilaments
Active transport
Transport that requires energy because it moves substances across a concentration gradient
Adventitious roots
Roots that grow above ground:
Agnostic behavior
Aggressive behavior
Fermentation
Process by which pyruvate and NADH are converted into CO?, NAD, and 2 ADP in the absence of O?
Allantois
Transfers respiratory gasses to the embryo in an egg
Allele
A form of a gene
Alviolus
Microscopic sites of diffusion of respiratory gasses in the lung
Amnion
Sac holding the protective amniotic fluid around an embryo in an egg
Amylase
Digestive enzyme that breaks down carbohydrates
The Islets of Langerhans
Endocrine organ of the pancreas. Secretes insulin, which lowers blood glucose levels, and glucagon, which increases blood glucose levels.
Analogous structures
Structures with different evolutionary origins but the same function as a result of convergent evolution
Aneuploidy
A chromosomal abnormality with 1 (monosomy) or 3 (trisomy) instances of a chromosome. Trisomy 21 causes down syndrome.
Angiosperm
Flowering plant
Tracheophyte
Vascular plants, including seeded and non-seeded plants
Bryophyte
Nonvascular plants with no leaves, including mosses
Ferns
Non-seeded vascular plants that reproduce with spores
Anther
The pollen-producing part of the stamen (plant male reproductive organ)
Antheridia
Structure on gametophyte generation that produces sperm by mitosis. Very prominent in mosses, but hidden inside anther in vascular plants.
Saprophyte
Organism (esp. fungi) that lives on decaying matter
Saprobe
Organism (esp. fungi) that lives on decaying matter
Antibodies
Y-shaped molecule that bonds to an antigen and signals the third line of defense - replication and phagocytosis
Antigen
Something from outside the body that triggers a response by antibodies
Anticodons
A three-nucleotide sequence that pairs to a codon and is attached to an amino acid my a tRNA molecule
Apoptosis
Programmed cell death
Archeopteryx
An intermediate fossil between reptiles and birds
Archegonia
Structure on gametophyte generation that produces egg by mitosis. Very prominent in mosses, but hidden inside anther in vascular plants.
Associative learning
A type of earning linking something to something else
ATP Synthase
Structure in the inner membrane of the mitochondria that produces ATP as H? flows through it
Autonomic nervous system
Unvoluntary part of the peripheral nervous system
Autosome
Non-sex chromosome
Autotroph
Makes chemical energy from light energy by photosynthesis
Auxin
Growth hormone in plants promoting apical dominance and phototropism
Protozoa
Animal-like protists
Backcross
Cross with aa to determine if an organism showing the dominant allele is homozygous or heterozygous - also testcross
Bicarbonate ion
Buffer in human blood made from CO? that keeps blood pH at 7.4
Bile
Emulsifier made by the liver and excreted by the gallbladder
ADD FUNCTIONS OF ORGANS
ADD FUNCTIONS OF ORGANS
Biomagnification
Organisms at higher trophic levels have greater concentrations of toxins
Biosphere
EARTH
Biotechnology
Branch of science combining bio and tech, including genetic engineering using recombinant DNA
Biotic potential
Maximum rate at which a population can increase under ideal conditions. Limited by life span, reproductive age, number reproductive periods, and number of offspring per reproductive period.
Bottleneck effect
A type of genetic drift in which a small non-selective group of individuals becomes separated from the larger population and forms a new species, which may or may not represent the original.
Buffers
Chemicals that resist a pH change
Budding
A new organism grows and splits off of an existing one - e.g. hydra, potatoes
C-4 Photosynthesis
Adaptation for dry environments
CAM (crassulation acid metabolism)
Adaptation of photosynthesis for dry environments to close stomates during day and open them at night
Calvin cycle
Process converting sugar to producing sugar in the stroma during the light-independent reactions
Cardiac/Pyloric sphincters
Smooth muscle at the top/bottom of the stomach
Carotenoids
Orange and yellow photosynthetic accessory pigments
Carpel
Female part of flower, including stigma, style, and ovary. Also called the pistil.
Carrying Capacity (K)
The maximum number of individuals capable of living in an area at the same time.
Cation/Anion
Positive/Negative Ion
Centrioles
ONLY animal cells. Responsible for the division of the cytoplasm, consisting of a 9 + 2 structure
Centromere
Connecting point of sister chromatids, place where spindle fibers attach in Metaphase
Centrosome
ONLY animal cells. Two centrioles at right angles, important in cell division
Chemiosmosis
The flow of protons through ATP synthase during oxydative phosphorylation in the inner membrane
Collenchyma cells
Thick single-walled plant cells - e.g. strings of celery
Colon
Large intestine - site of water absorption and vitamin production by gut bacteria
Commensalism
Symbiotic relationship in which one organism benefits and the is not affected
Community
All the organisms living in one geographical area
Chitin
Strong chain of glucose found in arthropod exoskeletons and fungi cell walls
Chorion
Membrane under egg shell allowing for the diffusion of respiratory gasses in and out of the shell
Chromatin network
DNA condenses into chromatins and is wrapped in histones
Chromoplasts
Plastid that stores pigment (carotenoids) and is responsible for the bright colors of fruits and flowers.
Classical conditioning
A type of associative learning in which an organism associates one this with another
Companion cells
Makes phloem with sieve tube elements
Conjugation
Bacteria exchange DNA plastids with each other
Continental drift
Theory stating that the continents were once Pangea
Contractile vacuole
Structure in freshwater protists that removes excess water
Convergent evolution
Evolution that causes two unrelated species to develop similar structures due to similar selective pressures
Cortex (plant)
Specialized region in root for storage and support - e.g. carrot
Cotyledon
Food for growing embryo in a dicot seed with triploid cells (3n)
Cristae
Series of inner membrane of mitochondria where cellular respiration occurs
Crop
Food storage area in annelids, insects, birds, etc.
Crossing-over
Homologous chromosomes exchange genes in prophase of meiosis I, leading to greater genetic variation
Cleavage
Rapid mitosis without growth after zygote formation and fertilization
Cnidocytes
Cniderians’ stingers
Codominance
Both traits are expressed like a black and white cookie - e.g. AB blood type
Codon
Thre-nucleotide sequence of mRNA
Coenzyme
Vitamins that aid enzymes
Cofactor
Minerals that aid enzymes
Cohesion tension
Molecules are attracted to themselves - e.g. water
Coevolution
Two interacting species evolve in response to each other - e.g. predator and prey
Cutin
Makes up the cuticle, the outer lauer ofplants that conserves water
Cyclosis
Movement of cytoplasm in cell
Cystic fibrosis
Autosomal recessive genetic mutation that causes water to build up in the lungs and digeative track
Cytocrome
Proteins that are involved in th ETCmitochondria and chloroplasts
Cytokinesis
Divisoon of cytoplasm in mitosis an meiosis. In animals, a cleaveage furrow forms, and in plants, a cell plate forms.
Cytokinins
Plant hrmones that stimulages cell division and cytokinesis
Cytosol
Semiliquid part of cytoplasm
Deletion
Part of a chromosome/nucleotide is lost
Denatured
Enzyme/protein unfolds a high temps or extreme pHs
Diastole
Blood is pumped from the atria to the ventricles (ventricles relax). Normal pressure is 80.
Assimilation
Proccess of converting nutrients into substances usable by the body
Dicotyledon
Division of angiosperms with two-sided seeds, a taproot, vascular bundles in ring, nonparallel veins, no endosperm, flowers in 4/5.
Dipeptide
Two amino acids liked by a peptide bond.
Epididymis
Tube connecting vas deferens to the testes
Directional seletion
Evolution gowards a particular phenotype because of changing environmental conditions
Disruptive selection
Evolution toward the extremes
Diversifying selection
Evolution toward the extremes
Divergent evolution
Section of a population undergoes speciation due to isolation
DNA Polymerase
Replicates DNA
Duodenum
First 10 inches of small intestine where digestion is completed
Ecosystem
All biotic and abiotic factors in an area
Ectoderm
Outer layer of embryo that forns the skin and nervous system
Ectotherm
Cold Blooded- Fishies, amphibians, and reptiles
Egestion
Removal of metabolc waste
Excretion
Removal of metabplic waste
Endoderm
Inner layer of embryo that forms viscera
Endosperm
Food for monocot seeds that is triploid (3n)
Endotherm
Warm-blooded –Birds, Mammals
Eohippus
Transition fossil from ancient horse
Epicotyl
Part of seed that forms upper stem and leaves
Epiglottis
Cartilage in pharynx that closes pathway to the larynx so that food flows to asophagus
Erythrocytes
Red blood cells that make 45% of blood and carry O2 in hemoglobin
Ethylene
Plant hormone that induces ripening
Eukaryotes over prokaryotes
Membrane-bound organelles –Linear Chromosomes, No Plastids, Cytoskeletal Elements like Microfilament 10-100um
Prokaryotes over eukaryotes
Only capsid, wall, membrane, chromosome, plastids, ribosomes. No Membrane-bound Organelles, One Circular Chromosomes, No plastids, No cytoskeletal Elements like microfilament 1-10um
Exocytosis
Release of substances from cell
Exon/Introns
Coding/noncoding portion of genes
Extremophile
Orgnisms that live in extreme environments. Thermophiles, Halophiles, Methanogens
Fallopian tube
Tube connective ovaries and uterus in which egg is fertilized. Also called oviduct.
Filament
Thread-like structure that holds up anther in stamen
Filtration
Blood filtered in glomerulus
Final trancript
Strand of mRNA sent to ribosomes after transcription - shorter than original transcript because introns are removed
Fission
Asexual replication by division, especially in bacteria and protists
Fixed action pattern
Innate, stereotypical behaviors that, once initiated, are always completed. Initiated by sign stimuli.
Founder effect
Form of genetic drift in which a section of a population, which may or may not represent the original population, breaks off to colonize a new area.
Fragmentation
Asexual reproduction in which an original organism breaks into multiple parts that regenerate into full new organisms. Reproduction in sponges, planaria, sea stars.
G3P (Glyceradehyde-3-phosphate)
Sugar produced at the end of the Calvin cycle
Gametanglia
Protective jacket of cells protecting gametes and zygotes in primitive plants
PGAL
Sugar produced at the end of the Calvin cycle
Gamephyte
The haploid generation that produces gametes by mitosis
Gastrin
Digestive hormone that tells the stomach to secrete gastric juice and acid
Gastrovascular cavity
Primitive digestive cavity in cnideria. Also gastrocoel
Gastrulation
Differentiation of the three cell layers in human development to go from a blastula to a gastrula
Gel electrophoresis
Process by which substances are identified by the rate at which they move through an agarose gel in an electric field. Smaller pieces of DNA cut by restriction enzymes move faster through the gel.
Gene flow
Movement of alleles in or out of a population
Genetic drift
Change in gene pool due to chance. Bottleneck and founder effect are examples.
Gibberellins
Plant hormones that promote stem and leaf elongation
Gizzard
Structure in annelids, arthropodes, and birds in which mechanical digestion of food occurs
Global warming
Warming of the globe caused by greenhouse effect of CO?
Glucagon
Hormone released by the pancreas that increases blood glucose levels (I think by targeting the liver to break down blood but maybe also the whole body have to check that)
Glycerol
Three-glucose top of a triglyceride
Glycolysis
Anaerbic breakdown of glucose into pyruvic acid (3C) that costs 2 ATP and releases 4 ATP, with a net gain of 2 ATP
Golgi apparatus
Packaging and transport of proteins from ribosomes throughout the cell
Gradualism
Disproved theory of evolution stating that speciation occurred slowly over time
Grana
Stacks of thylacoid membranes in the chloroplasts
Greenhouse effect
CO? and water vapor in the atmosphere absorbs the infrared radiation reflected off the Earth, increasing temperatures
Junk
Noncoding regions of DNA
Gross primary preductivity
Chemical energy produced by all producers in an ecosystem per unit time
Net primary productivity
Chemical energy produced by photosynthesis minus the energy used by respiration by the producers in an ecosystem per unit time
Guard cells
Epithelial cells that open and close the stomates and can perform photosynthesis
Gymnosperms
Coniferous plants with vascular tissue, seeds, but not flowers
Habituation
Behavior in which an organism learns to ignore a persistent stimulus
Halophiles
Organisms which can survive in extremely salty environments - archeans
Half-life
Amount of time it takes of a radioactive isotope to decay to half its mass
Heliobacter pylori
Bacteria that causes ulcer
Hemocoels
Blood-filled cavities surrounding organs in arthropods - also sinuses
Spiracles
Small holes in exoskeleton of arthropod for gas to enter the body, go through tracheal tubes, and diffuse into the blood.
Hemophilia
Sex-lined recessive gene that makes it difficult to clot blood
Hermaphrodites
Organisms with male and female sex organs - e.g. earthworms
Heterotroph hypothesis
Theory that organisms developed as anaerobic heterotrophic prokaryotes`
Heterotroph
Animals that obtain their food from the environment (not the sun)
Heterozygous hybrid
Aa
Histamine
Triggers vasodilation, the enlargement of blood vessels, and inflammation - also responsible for the symptoms of the common cold
Histones
Proteins that DNA wraps around, forming the chromatin network
Homeotherm
Endother - warm blooded –Birds, mammals
Homologous structures
Structures with tthe same evolutionary origins but different structures
Huntington’s disease
Autosomal dominant disease of the nervous system that results in early death
Hydrogen bonding
Intermolecular attraction of polar molecules
Hydrophobic
Nonpolar, insoluble in water
Hydrophilic
Polar or ionic, soluble in water
Hypertonic
Greater concentration of solute (salt)
Hypocotyl
Part of the embryo in a seed that becomes the lower stem and roots
Hypotonic
Less concentration of solute (salt)
Hyothalamus
Gland in brain that connects endocrine and nervous system - secretes tropic hormones to the pituitary
Imprinting
Learning to recognize a mother shortly after birth
Incomplete dominance
Neither trait dominates - red and white make pink
Ingestion
Intake of nutrients
Initial transcript
Longer strand of mRNA with introns
Insulin
Hormone released by the pancreas that decreases blood glucose levels by storing glycogen in the liver and increasing the rate of cellular respiration in the body’s cells
Inversion
Point mutation in which two nucleotides are switched. Chromosomal mutation in which a fragment breaks off and reattaches itself backwards
Insertion
Frame-shift mutation in which a nucleotide is inserted into a strand
Irritability
Ability to respond to stimuli
Isotonic
Solutions with equal concentration of solutes (salt), resulting in movement by diffusion but no change
Karyotype
Laboratory procedure that analyses the size, shape, and number of all 46 chromosomes
Krebs Cycle
First stage of the aerobic section of cellular respiration, in which acetyl-coA is broken down, CO? is released, 2 GTP is produced, and electron carriers NADH and FADH? are filled - also citric acid cycle
Lacteal
Absorbs lipids into lymphatic system in microvilli
Lactic acid fermentation
Fermentation in the body which results in the production of lactic acid, which builds up in the muscle and causes fatigue
Law of Dominance
Some traits of a gene dominate over others
Law of Independent Assortment
Genes on separate chromosomes are inherited seperately- best demonstrated by a dihybrid cross (9:3:3:1)
Law of Segregation
A persons’ two alleles from their two parents separate during miosis I - best demonstrated by hybrid cross
Leucoplast
Plastid stat stores starch - is a carrot an example or is that just a root
Leukocyte
White blood cell, including phagocytes, lymphocytes (B and T), and others
Light-dependent reactions
Reactions that occur in the thylacoid membrane of the chloroplast and split light into two, releasing O?, filling NADPH, and producing ATP
Light-independent reactions
Reactions that occur in the stroma, requires only the products of the light-dependent reactions, and produces PGAL/G3P
Limiting factors
Factors that limit the growth of a population growth in an area - divided into density-dependent and density-independent
Locomotion
Movement - can be done by muscles, pseudopods, flagella, cilia
Lysosome
Structure in animal cells that performs intracellular digestion with hydrolitic enzymes
Macroevolution
Speciation
Microevolution
Change in the gene pool of a population
Malpighian tubules
Tubes in arthropods that excrete substances (e.g. uric acid) from the digestive tract
Malthus
Proposed that populations outgrow their food supply
Medusa
Upside down bowl shaped body type (jellyfish)
Metapause
Cessation of the menstrual cycle
Mesoderm
Middle tissue layer in embryos that develops into the bones, muscles, and blood
Mesoglea
Glue that holds together the two body layers of two-layered animals - e.g. cnideria, platyhelminthese
mRNA
RNA transcribed from DNA that travels form the nucleus to the ribosomes
Methanogen
Extremophile (archean) that produce methane from hydrogen
Microfilaments
Supports cell shape, forms cleavage furrow in animal cells, helps amoeba move with pseudopods, made of actin
Microtubules
Thick hollow tubes that make up the cilia, flagella, and spindle fibers
Middle lamela
Layer of tissue between the cell walls of two adjacent plant cells
Monocotyledon
Division of angiosperms with seeds that do not break into two parts, fibrous roots (no taproot), scattered vascular bundles, parallel veins, endosperm, flowers in 3 - e.g. corn
Monohybrid cross
Aa x Aa
Monotremes
Egg-laying mammals which derive nutrient from a celled egg. e.g spiny anteaters , duck-billed platapus
Multiple alleles
More than 2 allele forms of a gene – e.g. blood type - A, B, O
Mutation
Change in a gene or chromosome
Mutualism
A symbiotic relationship where both organisms benefit e.g. gut bacteria
Mycorrhiza
Symbiotic structures consisting of the plants roots and the hyphae (filaments) of a fungus, which increase the quantity of nutrients and water the plant can absorb.
Myosin
Myofilaments that make up the sarcomeres of skeletal muscles with actin
NAD/FAD
Coenzyme that shuttles electrons and protons from glycolysis and the Krebs cycle to the ETC
Nephridia
Structures in annelids for the excretion of nitrogenous waste in the form of urea
Nondisjunction
Homologous chromosomes do not separate correctly during anaphase of meisis I
Notochord
Rod that extends the length of the body, serving as a flexible axis - characteristic of chordates
Nucleolus
Structure inside the nucleus that produces rRNA, or ribosomes
Objective lens
Lens on a light microscope closest to the stage, that can be switched for varying degrees of magnification
Occular lens
Lens on top of magnifying class that has a fixed magnification, usually 10X
Oogenesis
Production of an ovum and two polar bodies from an oogonium/oocyte by meiosis
Operant conditioning
Learning by trial and error / punishment and reward
Organogenesis
Formation of organs from the 3 embryonic germ layers
Origins of replication
Special sites where replication begins in eukaryotic cells
Osmosis
Diffusion of water across a membrane
Oviduct
Tube connective ovaries and uterus in which egg is fertilized. Also called the Fallopian tube
Ovule
The structure within the ovary in which the ova develop and becomes the seed
Oxidation
Removal of electrons
Reduction
Gain of electrons
Oxydative phosphorylation
Proccess producing about 30 ATP during cellular respiration in the inner membrane of the mitochondria Also the electron transport chain.
Oxytoxin
Hormone from the posterior pituitary that stimulates contraction of the uterus during childbirth and the formation of breastmilk
Pangaea
Supercontinent of all land
Parallel evolution
Two closely related species evolve similar traits under similar environmental pressures
Parasitism
Symbiotic relationship in which one organism benefits and one is harmed
Parenchymal cells
Traditional plant cells with a thin primary cell was
Parthenogenesis
Development of an egg without fertilization to form haploid child by mitosis
Pathogen
Organism that causes
Pedigree
Family tree indicating the phenotype of one train
Petidases
Enzymes that break down proteins
Phagocytosis
Engulfing food into a vacuole - a form of enocytosis
Pharynx
Where the digestive and respiratory tracks meet in the throat
PKU (Phenylketonuria)
Autosomal recessive trait in which one cannot break down phenolthalein, which will harm their brain
Photolysis
Splitting of H?O in chlorophyll a to replenish the lost electrons of the ETC, fill NADPH, and release O?
Photosynthetic pigments
Chemicals that absorb light energy and use it to perform photosynthesis, including chrolophyll a, chlorophyll b, carotenoids, and phycombilins
Phycombilins
Photosynthetic pigments, found most often in cyanobacteria and red algae
Pinocytosis
Cells take up large dissolved molecules by ‘cell drinking,’ a form of endocytosis
Pioneer organism
First organisms to colonize a barren environment in primary ecological succession, such as lichens, a combination of fungi and algae
Pistil
Female part of flower, including stigma, style, and ovary. Also called the carpel.
Pith
Tissue in the stems of vascular plants —–[Specialized region in the plant root for storage] - What Barrons says that may not be correct
Plasma
Liquid portion of blood containing gasses, proteins, hormones, water, etc.
Plasmodesmata
Openings in cell walls in plants for transport
Plasmolysis
Cell shrinking when cell is in a hypertonic environment
Plastids
Organelles found only in plant cells
Polarized
Condition of an axon at rest (-70mV) - also resting potential
Polygenic
More than two alleles contribute to the expressed phenotype. e.g. hair color
Polymerse Chain Reaction (PCR)
A fragment of DNA is replicated many times and studied
Polymers
Molecules that are chains of repeating smaller molecules
Polyp
Vase-shaped body - e.g. cnideria
Polyploid
An organism with extra sets of chromosomes (3n, 4n…) - common in plants
Population
Group of individuals of the same species in a single area
Primary Growth
Vertical growth in a plant from apical meristem
Prions
Misfolded proteins - e.g. cause Mad Cow Disease
Prostate gland
Large gland that secretes semen into the urethra
Pseudopods
Extensions of the cell - how amoebas and white blood cells move
Punctuated equilibrium
Theory that replace gradualism, proposing that speciation occurs suddenly after long periods of stasis
Purines
Adenine and guanine – Double ring
Puberty
Onset of sperm production in males and menstrual cycle in females
Pyrimidines
Thymine, cytosine, and uracil – Single ring
Radioisotope
Radioactive isotopes – Iodine 131 is used to detect diseases of the thyroid
Reabsorbtion
Water and nutrients are reabsorbed from the nephron of the kidney into blood capillaries
Receptor-mediated endocytosis
Endocytosis of specific substances recognized by a specific receptor on the ecell
Recognition sequences
Places at which restriction enzymes cut DNA
Recombinant DNA
Technique of combining fragments of DNA into a single strand - genetic engineering
Redox
Combination of reduction and oxydation reactions
Reductive division
Another name for Meisis I, where homologous pairs cross over and separate
Releaser
Sign stimuli exchanged between members of the same species
Replication bubbles
Sections of DNA where the strands separate in order to speed up the process of replication
Replication fork
Y-shaped region where the new strands of DNA are elongating during DNA replication
Cellular respiration
Metabolic process with the main purpose of creating ATP
Restriction enzymes
Cut DNA at specific recognition sequences or sites, such as GAATTC - extracted from bacteria
Restriction fragments
Fragments that result from DNA cur by restriction enzymes
Rhyizobium
Symbiotic bacteria that live on the root nodules of legumes that fix bacteria into ammonia
Nitrifying bacteria
Convert ammonia from nitrogen fixing bacteria into nitrates (NO??)
Nitrogen fixing bacteria
Convert atmospheric nitrogen (N?) from the air into ammonia (NH??)
Denitrifying bacteria
Convert nitrates (NO??) into atmospheric nitrogen (N?)
rRNA
Structural rRNA synthesized in nucleolus that make up the ribosome
Ribosome
Structure in cell where proteins are synthesized (translation)
RNA Processing
Occurs in the nucleus before the newly formed mRNA is sent to the ribosome
Saprobes
Organisms that obtain nutrients from dead organic matter
Sclerenchyma cells
Thick, double-walled cells fortified with lignin whose only purpose is support
Apoplast
Network of cell walls and spaces in a plant body that allows for the extracellular movement of water.
Symplast
Continuous system of cytoplasm connected by plasmodesmata, openings in plants’ cell walls
Lateral movement
Movement of water and nutrients in a plant through the apoplast and symplast
Scrotom
Sac holding and cooling the testes
Secondary growth
Lateral growth of a plant
Secretin
Digestive hormone stimulating the pancreas to release bicarbonate to neutralize the acid in the duodenum
Secretion
Process in the tubule of the nephron in which substances that were not filtered in the Bowman’s capsule are released
Semiconservative replication
The theory that the two DNA strands separate and then individually replicate
Sepals
Outermost circle of green leaves around a flower that protect the bud
Serum
Plasma with no clotting factors
Sessile
Nonmoving
Sex-influenced trait
Inheritance is influenced by the sex of the individual
Sex-linked trait
Trait carried on the X chromosome
Sieve tube elements
Make up phloem along with transport vessels
Sign stimuli
Stimulate fixed action patterns - called releasers when from a member of the same species
Sinoatrial node
The pacemaker of the heart
Sinuses
Cavities in the body for the exchange of fluid - also hemocoels in arthropods
Sister chromatids
Exact copies of one another, but still the same chromosome
Spliceosome
Special molecules that assist in the removal of introns in RNA processing
Sodium-potasium pump
Molecule that pumps NA? outside the cell and K? inside the cell to return it to a polarized state
Solute
Substance dissolved in the solvent
Solvent
Substance the solute is dissolved into
Somatic cells
Body cells (non-sex)
Species
Group of organisms that can reproduce to produce viable, fertile offpring
Spermatogenesis
Formation of 4 sperm cells from one spermatogonium by meiosis
Spindle fibers
Attach to the centromeres of chromatids in mitosis and meiosis - made of microtubules
Spontaneous generation
Theory that life emerged from nothing - disproved by Redi and Pasteur
Sporophyte
Diploid (2n) generation of a plant that is dominant in vascular plants
Sporopollenin
Tough polymer that protects spores, pollen, and plants in a harsh environment
Stabilizing selection
Selection towards intermediate organisms away from the extremes
Stamen
Male part of a flower composed of filament and anther
Stele
Vascular cylinder in a plant root - much smaller in dicots than monocots
Stomates
Openings in the leaves of plants for gas exchange (H?O, O?, CO?)
Stroma
Part of chloroplast holding the grana where light independent reactions take place
Substrate level phosphorylation
Process by which ATP is produced in glycolysis and the Kreb’s cycle - opposite of oxidative phosphorylation
Synapsis
Process by which homologous chromosomes par up in prophase I of Meiosis
Synapse
Gap between neurons in which neurotransmitters are released by vesicles and bind to receptors on the dendrites of the next neuron
Systole
Contractions of the ventricles, moving blood through the semilunar valves
Semilunar valves
Valves that connect the ventricles to arteries - aortic on the left and pulmonary on the right
Bicuspid valve
Valve preventing backflow into the left atrium — Also mitral valve or left atrioventricular valve
Mitral valve
Valve preventing backflow into the left atrium — Also bicuspid valve or left atrioventricular valve
Tricuspid valve
Valve preventing backflow into the right atrium — Also right atrioventricular valve
Taproot
Single, large root in dicots - e.g. carrot
Taxon
Level of organization of organisms: DKPCOFGS
Taxonomy
Science of classification
Tay-Sachs disease
Autosomal recessive trait causing an inability to break down lipids needed for the brain
Telomeres
Nonsense regions at the end of chromosomes repeated thousands of times
Testcross
Cross with aa to determine if an organism showing the dominant allele is homozygous or heterozygous - also backcross
Testes
Male gonads that produce sperm and testosterone
Theory of endosymbiosis
Theory that eukaryotes developed from smaller prokaryotes living inside bigger prokaryotes
Thermophiles
Organisms that live in extremely hot environments - archeans
Thrombocytes
Cell fragments that clot blood - also platelets
Thylacoids
Membranes in the grana of chloroplasts where the light-dependent reactions occur
Tracer
Radioactive isotope used to track a substance
Tracheid
Cells that make up xylem along with vessel elements
Transcription
Process that produces mRNA from DNA in the nucleus
Translation
Process that produces proteins from mRNA in the ribosome
tRNA
Carries amino acids to the ribosome and assembles proteins by matching codons with anticodons
Transformation
Bacteria pick up plasmids from their environment
Translocation
A fragment of a chromosome is attached to a non-homologous chromosome - error in anaphase I of meiosis
Transpiration
Loss of water from the stomates of plant leaves
Transpiration-pull cohesion tension
Tension that pulls water molecules up the xylem without using energy
Trichomes
Tiny, spikelike projections on some leaves for protection
Triploblastic
Animal with three cell layers - all animals more complex than platyhelminthese
Trisomy
Three copies of a single chromosome - trisomy 21 causes down syndrome
Tropic hormones
Hormones that stimulate other glands to release hormones
Tropism
Growth of a plant toward or away from a stimulus - e.g. geotropism, thigmotropism, phototropism
Turgor pressure
Pressure exerted on cell wall when plant cell swells
Ultracentrifuge
Machine that separates substances (often organelles) by spinning at high speeds
Urethra
Tube that carries semen and urine in males and urine in females
Uterus
Where the blastula implants and develops after fertilization in the oviduct
Vacuoles
Large organelles for the function of storage found mostly in plant cells
Vas deferens
Duct carrying sperm from testes
Vegetative propogation
Asexual reproduction in a plant - e.g. grafting, cutting, bulbs, runners
Vesicles
Small vacuoles - e.g. store neurotransmitters in neurons
Vsssel elements
Make up xylem along with tracheids
Vestigal structures
Unused structures that remain from an ancestor - e.g. appendix, vestigial tail
Villus
Tiny projections that increase surface area in the small intestine and absorb nutrients into capillaries (and lipids into lacteals)
Wave of depolarization
Condition of an axon during an action potential in which the NA? rushes into the cell, making it more positive
Xylem
Vessels in plants that transport water without energy loss and are made of tracheids and vessel elements
Yolk sac
Membrane enclosing and providing food for an embryo in an egg