Bio Exam

Cell Structures

* Term: Organelles

* Definition: Internal functional structures of a cell

* Term: Plasma membrane

* Definition: A dynamic barrier that surrounds the cytosol of the cell

* Term: Nucleus

* Definition: An organelle that contains almost all DNA in a eukaryotic cell

* Term: Nuclear envelope

* Definition: Two lipid bilayers folded together that enclose the nucleus

* Term: Mitochondria

* Definition: An organelle with two membranes; the site of most ATP synthesis during aerobic cellular respiration

* Term: Plastids

* Definition: A membrane-bound organelle that is involved in photosynthesis and storage in plants and algae

* Term: Chloroplasts

* Definition: A double-membrane-bound organelle that contains enzymes and pigments that are used to perform photosynthesis in eukaryotic cells

* Term: Cytoskeleton

* Definition: A dynamic system of filaments that provides cell structure, helps with cell division, and enables the cell and inner organelles to move around

* Term: Cell wall

* Definition: The outer barrier of a plant cell; surrounds cell membrane and provides structural support

* Term: Extracellular matrix (ECM)

* Definition: A molecular system that supports and protects a cell

Cellular Respiration and Fermentation

* Term: Cellular respiration

* Definition: A process where mitochondria synthesize ATP

* Term: Citric Acid Cycle

* Definition: A metabolic cycle where acetyl groups are oxidized to CO2, producing ATP and electron carriers

* Term: Acetyl-CoA

* Definition: A molecule that enters the citric acid cycle, formed from pyruvate

From Gene to Protein

* Term: Messenger RNA (mRNA)

* Definition: The end product of the transcription of a gene; translated by ribosomes into a protein

* Term: Transfer RNA (tRNA)

* Definition: A carrier molecule that binds to a specific amino acid and adds it to a growing polypeptide chain

* Term: Ribosomal RNA (rRNA)

* Definition: An RNA molecule within the ribosome that bonds the correct amino acid to the polypeptide chain

* Term: RNA polymerase

* Definition: An enzyme that reads a DNA strand and creates a complementary strand of RNA

* Term: Template strand

* Definition: The complementary base pair of the coding strand, read by RNA polymerase

* Term: Transcription

* Definition: The process where RNA polymerase reads a DNA strand and creates a complementary strand of RNA

* Term: Translation

* Definition: The process where mRNA associates with a ribosome, and amino acids are linked to create a protein

* Term: One gene–one enzyme hypothesis

* Definition: The hypothesis that each gene is unique and codes for the synthesis of a single enzyme

Homeostasis and Feedback Mechanisms

* Term: Negative feedback

* Definition: A process where the effects of a mechanism slow or stop the mechanism

* Term: Sensor

* Definition: A component of a feedback system that detects changes in the internal environment

* Term: Integrator

* Definition: A component of a feedback system that sorts and interprets neural messages

* Term: Setpoint

* Definition: The target value of a physiological variable in a feedback system

* Term: Effector

* Definition: A component of a feedback system that carries out the response

Manipulating and Cloning DNA

* Term: Restriction enzymes

* Definition: Enzymes that chop DNA at specific sequences to protect prokaryotic cells from viruses

* Term: Blunt end

* Definition: The end that remains after restriction enzymes cut straight across a DNA strand

* Term: Sticky end

* Definition: The end that remains after restriction enzymes cut on a zigzag across a DNA strand

* Term: DNA ligase

* Definition: An enzyme that joins cut strands of DNA

* Term: Plasmids

* Definition: Small circular pieces of DNA that are found in bacteria and replicate independently of chromosomal DNA

* Term: Competent cell

* Definition: A cell that is able to take up foreign DNA from its surroundings

* Term: Vector

* Definition: A DNA molecule that is used as a vehicle to transfer foreign genetic material into a cell

* Term: Transformation

* Definition: The successful introduction of DNA from another source into a cell

* Term: Hybridization probe

* Definition: A fragment of DNA that is used to detect the presence of complementary nucleotide sequences

Photosynthesis

* Term: Chloroplast

* Definition: Organelle where photosynthesis occurs, containing three membranes and distinct spaces

* Term: Thylakoid membranes

* Definition: Interconnected stacks of flattened discs where light-dependent reactions occur

* Term: Stroma

* Definition: Fluid within the inner membrane of a chloroplast, where the Calvin cycle occurs

* Term: Photosystem

* Definition: Organized pigment proteins that absorb light energy

The Fundamental Chemistry of Life

* Term: Protons

* Definition: Positively charged subatomic particles that determine the identity of an atom

* Term: Neutrons

* Definition: Neutral subatomic particles found in the nucleus of an atom

* Term: Electrons

* Definition: Negatively charged subatomic particles that occupy orbitals around the nucleus

* Term: Isotope

* Definition: An atom of an element with the same number of protons but a different number of neutrons

* Term: Hydrolysis reactions

* Definition: A chemical reaction in which water is used as a reactant to split a larger molecule into smaller subunits

* Term: Redox Reactions

* Definition: Reactions where electrons are lost from one atom and gained by another

* Term: Oxidation

* Definition: A reaction in which a molecule loses electrons

* Term: Reduction

* Definition: A reaction in which a molecule gains electrons

The Role of the Nervous System

* Term: Afferent neuron

* Definition: A neuron that carries impulses from sensory receptors to the central nervous system (also called a sensory neuron)

* Term: Interneuron

* Definition: A local circuit neuron of the central nervous system that relays impulses between afferent and efferent neurons

* Term: Efferent neuron

* Definition: A neuron that carries impulses from the central nervous system to skeletal muscles (also known as a motor neuron)

* Term: Dendrites

* Definition: Highly branched projections that receive signals and transmit them toward the cell body

* Term: Axon

* Definition: Specialized projections that conduct signals away from the cell body to another neuron or an effector

* Term: Axon terminals

* Definition: Small, button-like swellings on the end of an axon that act as the points of connection that enable the signals to be transmitted

* Term: Glial cell

* Definition: A non-conducting cell that is important for the structural support and metabolism of nerve cells

* Term: Myelin sheath

* Definition: Tightly wrapped layers of plasma membrane formed from Schwann cells; act as electrical insulators due to high lipid content

* Term: Nodes of Ranvier

* Definition: Gaps between Schwann cells; expose axon membrane to ECF

* Term: Reflex arc

* Definition: Simplest neural circuit that travels through the spinal cord but does not require the coordination of the brain; allows for reflex actions

Cellular Respiration - Glycolysis and Pyruvate Oxidation

* Term: Glycolysis

* Definition: The breakdown of glucose into two molecules of pyruvate

* Term: Pyruvate oxidation

* Definition: The process where pyruvate is converted into acetyl-CoA

DNA Sequencing

* Term: Polymerase Chain Reaction (PCR)

* Definition: A process that is used to make a huge number of copies of a DNA sequence in a laboratory

* Term: DNA primer

* Definition: A short single-stranded DNA sequence, easily synthesized in a laboratory, that is complementary to a sequence at one end of the target sequence

* Term: Gel electrophoresis

* Definition: A method for separating large molecules, such as DNA, RNA, and proteins

* Term: Structural genomics

* Definition: The study of the structure of genes and their locations in a genome

* Term: Functional genomics

* Definition: The study of the functions of genes, the proteins they make, and how these proteins function

* Term: Bioinformatics

* Definition: The use of computer technology to process a large amount of biological data

* Term: DNA microarray

* Definition: A solid surface that has a microscopic grid of many DNA fragments attached, used to determine gene expression and function

DNA-Directed RNA Synthesis

* Term: Poly(A) tail

* Definition: A chain of adenine nucleotides that are added to the 3’ end of the pre-mRNA molecule to protect it from enzymes in the cytosol

* Term: Alternative splicing

* Definition: A process where some introns are considered exons, and exons are considered introns, resulting in multiple different related proteins from pre-mRNA

Membrane Structure and Functions

* Term: Fluid Mosaic Model

* Definition: The idea that a biological membrane consists of a fluid phospholipid bilayer, in which proteins are embedded and float freely

* Term: Peripheral membrane protein

* Definition: A protein on the surface of the membrane

Nerve Signals

* Term: Synapse

* Definition: A functional connection between neurons or between neurons and effectors

* Term: Chemical synapse

* Definition: A synapse in which a neurotransmitter moves from a presynaptic cell to a postsynaptic cell through the synaptic cleft

* Term: Neurotransmitter

* Definition: A chemical that is released from vesicles into synapses to facilitate nerve signal transmission

* Term: Electrical synapse

* Definition: A synapse in which the presynaptic cell makes direct contact with the postsynaptic cell, allowing current to flow via gap junctions between the cells

* Term: Action potential

* Definition: The voltage difference across a nerve cell membrane when the nerve is excited

Pathways of Photosynthesis - Light Rxns

* Term: Photosystem II

* Definition: A photosystem that splits water into electrons, protons, and oxygen

* Term: P680

* Definition: The chlorophyll a molecule in the reaction center of Photosystem II

The Endocrine System

* Term: Pituitary gland

* Definition: A two-lobed gland within the cranial cavity that produces hormones that control the other endocrine glands

* Term: Tropic hormones

* Definition: Hormones secreted by the anterior pituitary gland that control endocrine glands elsewhere in the body

Thermoregulation and Water Balance

* Term: Torpor

* Definition: A short-term state of reduced metabolic rate and body temperature

* Term: Hibernation

* Definition: A state of greatly reduced metabolic rate and activity that enables an animal to survive the winter

Water

* Term: Autoionization

* Definition: The process in which a molecule spontaneously dissociates into ions

* Term: Buffer

* Definition: A chemical that compensates for pH changes in a solution by accepting or donating H+ ions

Cellular Respiration - The Citric Acid Cycle and The Electron Transport Chain

* Term: ATP synthase

* Definition: A structure that spans the inner mitochondrial membrane and synthesizes ATP using the H+ gradient

Pathways of Photosynthesis - Dark Rxns

* Term: Carbon fixation

* Definition: The conversion of carbon from an inorganic to an organic form

* Term: RuBisCO

* Definition: An enzyme that catalyzes the reaction of RuBP with CO2 in the Calvin cycle

Regulating Blood Sugar

* Term: Insulin

* Definition: A hormone that promotes the uptake of glucose by cells

* Term: Glucagon

* Definition: A hormone that stimulates the breakdown of glycogen to increase blood glucose levels

The Central Nervous System (1) & The Central Nervous System

* Term: Grey matter

* Definition: The tissue of the brain and spinal cord where the cell bodies and dendrites of neurons are located

* Term: White matter

* Definition: The tissue of the brain and spinal cord, composed primarily of axons of neurons

* Term: Medulla oblongata

* Definition: The hindbrain region that connects the spinal cord to the cerebellum; important in autonomic nerve control

* Term: Cerebellum

* Definition: The hindbrain region that is involved in muscle movement and balance

* Term: Cerebrum

* Definition: The forebrain; the brain region that is involved in motor activities and sensory information

* Term: Cerebral cortex

* Definition: The outermost layer of the cerebral hemisphere

* Term: Hypothalamus

* Definition: A small conical area in the brain that regulates basic homeostatic functions

* Term: Basal nuclei

* Definition: Grey-matter centers that surround the thalamus on both sides of the brain and moderate voluntary movements

* Term: Blood-brain barrier

* Definition: A barrier formed by tight junctions between endothelial cells in the capillaries in the brain that blocks the movement of most substances into the brain via the bloodstream

The Excretory System

* Term: Nephron

* Definition: The functional unit of the kidney

* Term: Proximal convoluted tubule

* Definition: The duct portion of a nephron that connects the Bowman’s capsule to the loop of Henle

* Term: Loop of Henle

* Definition: The U-shaped part of the duct that connects the proximal convoluted tubule to the distal convoluted tubule

* Term: Distal convoluted tubule

* Definition: The duct portion of a nephron that connects the loop of Henle to the ducts that lead to the renal pelvis

Translation_ Nucleic Acid to Polypeptide

* Term: Anticodon

* Definition: A 3-nucleotide segment on a tRNA that pairs with a codon in an mRNA

* Term: Aminoacylation

* Definition: The process of adding an amino acid to a tRNA

* Term: Ribosomes

* Definition: Organelles that carry out protein synthesis by translating mRNA into chains of amino acids

Transport Across Membranes

* Term: Passive transport

* Definition: The movement of molecules across a membrane without the need for cellular energy

* Term: Simple diffusion

* Definition: The movement of molecules across a membrane down their concentration gradient

* Term: Facilitated diffusion

* Definition: The movement of molecules across a membrane with the help of transport proteins

* Term: Transport protein

* Definition: A protein that facilitates the movement of molecules across a membrane

* Term: Channel protein

* Definition: A transport protein that forms a channel through the membrane

* Term: Carrier protein

* Definition: A transport protein that binds to molecules and changes shape to move them across the membrane

* Term: Osmosis

* Definition: The diffusion of water across a semipermeable membrane

* Term: Active transport

* Definition: The movement of molecules across a membrane using cellular energy

Alternate Pathways to Photosynthesis

* Term: Photorespiration

* Definition: A process where rubisco binds with oxygen instead of carbon dioxide, wasting energy

* Term: C4 cycle

* Definition: An alternative pathway for carbon fixation that occurs in plants that live in hot, dry climates

* Term: CAM

* Definition: (crassulacean acid metabolism) An alternative pathway for carbon fixation that allows plants to conserve water

Carbohydrates and Lipids

* Term: Carbohydrates

* Definition: A biomolecule that consists of C, H, O, often used for energy or structural support

* Term: Monosaccharides

* Definition: The simplest type of carbohydrate, a single sugar molecule

* Term: Fatty acid

* Definition: A molecule consisting of a carboxyl group and a hydrocarbon chain

* Term: Saturated fatty acid

* Definition: A fatty acid whose carbon chain holds the maximum amount of hydrogens

Controlling Gene Expression

* Term: Operon

* Definition: A model of gene expression where a group of genes are transcribed together

* Term: Corepressor

* Definition: A signal molecule that binds to a regulatory protein to reduce the expression of an operon’s genes

* Term: Methylation

* Definition: A process where methyl groups are added to DNA to inactivate genes

* Term: Oncogene

* Definition: A gene that, when mutated, can cause the cell to divide uncontrollably

Reproductive Hormones

* Term: Gonads

* Definition: Glands responsible for the production of sex hormones, as well as the egg and sperm cells

* Term: Androgens

* Definition: Predominantly male sex hormones that control sexual development and reproduction

* Term: Corpus luteum

* Definition: A yellow body that develops from follicle cells after ovulation, which secretes hormones

* Term: Spermatogenesis

* Definition: The production and development of sperm cells in the testes

The Efficiency and Regulation of Cellular Respiration

* Term: Metabolic rate

* Definition: The rate at which an organism uses energy

* Term: Basal metabolic rate

* Definition: The minimum rate of energy expenditure of an organism when it is at rest

The Peripheral Nervous System

* Term: Spinal nerves

* Definition: 31 pairs of nerves that transmit signals between the spinal cord and the rest of the body

* Term: Substantia gelatinosa (SG)

* Definition: A band of grey matter in the spinal cord that, when stimulated, produces a neurotransmitter that communicates with an injured region of the body

Anaerobic Pathways

* Term: Anaerobic Respiration

* Definition: Respiration that uses electron acceptors other than oxygen

DNA Organization in Eukaryotes and Prokaryotes

* Term: Supercoiling

* Definition: The continuous twisting of prokaryotic DNA that reduces the volume of the DNA

Genetic Mutations

* Term: Genetic mutations

* Definition: Changes in the DNA sequence, caused by various mechanisms

* Term: Point mutation

* Definition: A change in a single nucleotide within a gene

* Term: Substitution

* Definition: The replacement of one base pair in a DNA sequence by another base pair

Proteins and Nucleic Acids

* Term: Proteins

* Definition: A large molecule that consists of many amino acid subunits joined together by peptide bonds

* Term: Amino Acids

* Definition: A molecule that contains a carboxyl group and an amino group; serves as the monomer subunit of proteins

* Term: Polypeptide

* Definition: A peptide with more than 50 amino acids

* Term: Denaturation

* Definition: The loss of both the structure and function of a protein due to extreme conditions

* Term: Nucleic acids

* Definition: Molecules that serve as the assembly instructions for all proteins in living organisms

* Term: DNA

* Definition: Deoxyribonucleic acid, stores hereditary information

* Term: RNA

* Definition: Ribonucleic acid, involved in protein synthesis

* Term: Nucleotide

* Definition: The building block of nucleic acids; consists of a 5-carbon sugar, a nitrogenous base, and one to three phosphate groups

The Senses

* Term: Mechanoreceptors

* Definition: Sensory receptors that are embedded in human skin that detect touch

* Term: Chemoreceptors

* Definition: Sensory receptors that sense chemicals

Enzymes

* Term: Enzyme

* Definition: A biological catalyst, usually a protein, that speeds up a chemical reaction

* Term: Substrate

* Definition: A specific reactant that an enzyme binds to

* Term: Active site

* Definition: The area on the enzyme where the substrate binds

* Term: Cofactor

* Definition: A non-protein group that binds to an enzyme and is essential for catalytic activity

* Term: Coenzyme

* Definition: An organic molecule that acts as a cofactor of an enzyme