bio exam

Functional group

A small reactive group of atoms that is a part of macromolecules and affects their function by participating in chemical reactions. They are usually ionic or strongly polar.

Phospholipids

Lipids that consist of two fatty acids and a phosphate group bound to glycerol. They are the primary lipids of cell membranes and have a hydrophilic head and two hydrophobic tails.

Dehydration synthesis

A reaction type where smaller subunits come together to form a larger molecule by removing water.

Condensation reaction

Same as a dehydration reaction, where smaller subunits come together to form a larger molecule by removing water.

Hydrolysis

Adding water to break molecules, splitting a larger molecule into smaller subunits. It is the reverse of dehydration.

First Law of Thermodynamics

Energy can be transferred or transformed from one form to another but cannot be created or destroyed. Total energy remains constant in any closed system.

Second Law of Thermodynamics

In every energy transfer/conversion, some of the useful energy in the system becomes unusable and increases the entropy (disorder) of the universe.

Lipids

Nonpolar compounds made up of hydrogen and carbon, with smaller amounts of oxygen. They have a structural backbone from fatty acids and can be categorized into fats, phospholipids, steroids, and waxes.

Carbohydrates

Sugar molecules consisting of carbon, oxygen, and hydrogen. They can be used as an energy source, for cell communication, and as building blocks. Monosaccharides, disaccharides, and polysaccharides are types of carbohydrates.

Proteins

Large molecules consisting of many amino acid subunits joined together by peptide bonds and folded into a three-dimensional shape. They have various functions and can be categorized into structural, defensive, signal, carrier, recognition and receptor, enzyme, and motile proteins.

Rubisco

The most abundant protein.

Nucleic acids

Polymers of nucleotides that serve as the assembly instructions for all proteins in living organisms. They contain hereditary information and include DNA and RNA.

Oxidation

The loss of electrons. NADH is the reduced form, while NAD+ is the oxidized form.

Reduction

The gaining of electrons. NAD+ gains electrons from a hydride to become NADH.

Photosynthesis

The process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar. It has two stages:light-dependent and light-independent reactions.

Fermentation

An anaerobic process that uses an organic compound as the final oxidizing agent. Two forms of fermentation are alcohol fermentation and lactate fermentation.

Chemiosmotic theory

The theory proposed by Peter Mitchell that describes ATP synthesis by pumping protons across the inner mitochondrial membrane, creating a proton gradient.

DNA

Consists of chains of nucleotides made up of deoxyribose, phosphate groups, and one of the four bases A, T, G, or C. It is twisted into a double helix shape.

RNA

Similar to DNA, but with a ribose sugar and the base thymine replaced with uracil. It is single-stranded and has three types:mRNA, tRNA, and rRNA.

Chargaff's rule

In DNA, the amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine.

Base Pair Rule

In DNA, the amount of G = the amount of C and the amount of A = amount of T.

Pyrimidines

Bases with a single-ring structure, including thymine, uracil, and cytosine.

Purines

Bases with a double-ring structure, including adenine and guanine.

Transcription

The process of rewriting the DNA code as an RNA code, occurs in the nucleus.

Translation

The process of converting the RNA code into a protein, occurs in the cytoplasm.

tRNA

Transfer RNA, carries amino acids to the ribosome during translation.

Anticodon

A sequence of three nucleotides on tRNA that is complementary to a specific codon on mRNA.

Promoter region

A specific DNA sequence where RNA polymerase binds to initiate transcription.

RNA polymerase

Enzyme responsible for synthesizing an mRNA strand during transcription.

Terminator

A DNA sequence that signals the end of transcription.

Poly-A-tail

A sequence of 200 adenine nucleotides added to the 3' end of mRNA for stability.

Splicing

The removal of introns (non-coding regions) from pre-mRNA by spliceosomes.

5' cap

A modified guanine nucleotide added to the 5' end of mRNA for protection.

Start codon

The universal codon AUG that initiates translation.

Ribosome

The cellular structure where translation occurs.

Stop codon

A codon that signals the end of translation.

Complementary base pairing

The specific hydrogen bonding between adenine-thymine and cytosine-guanine.

Restriction enzymes

Enzymes that cut DNA at specific recognition sites.

Point mutations

Small-scale mutations that involve a change in a single nucleotide within a gene.

Frameshift mutation

Mutations that occur when one or more nucleotides are inserted or deleted from a DNA sequence, causing a shift in the reading frame.

Homeostasis

The physiological state in which internal conditions are kept within a suitable range for life processes.

Nitrogen waste

Waste products produced from the breakdown of nitrogenous compounds.

Glomerular filtrate

The fluid filtered from the blood in the glomerulus of the kidney.

ADH (antidiuretic hormone)

A hormone produced in the brain that controls water balance in the body.

Autonomic division

The division of the peripheral nervous system that controls involuntary functions.

Neuron

A specialized nerve cell that transmits signals in the nervous system.

Afferent neuron

Sensory neuron that transmits stimuli from sensory receptors to interneurons.

Efferent neuron

Motor neuron that carries impulses from the central nervous system to muscles and glands.

Neural circuit

A network of interconnected neurons that transmit and process information.

Endocrine system

The system that regulates hormone levels in the body.

Action potential

The voltage difference across a nerve cell membrane when a nerve is excited.

Threshold potential

The membrane potential at which an action potential is generated.

Refractory period

The resting period of a neuron when the threshold is higher than normal.

Glucagon

A hormone that stimulates the breakdown of glycogen to glucose.

Body mass

The weight of individuals within a population.

Population density

The number of individuals per unit area or volume.

Exponential growth

Rapid reproduction and expansion of a population under favorable conditions.

Competitive inhibitors

Molecules that inhibit enzyme activity by binding to the active site and competing with the substrate.

Non-competitive inhibitors

Molecules that inhibit enzyme activity by binding to a different site on the enzyme, causing a change in its shape.

Alpha glucose

Glucose with the hydroxyl group on carbon #1 below the ring.

Beta glucose

Glucose with the hydroxyl group on carbon #1 above the ring.

Mitochondria

The organelle where cellular respiration occurs.

Glycolysis

The process of breaking down glucose into pyruvate in the cytosol.

Pyruvate

The end product of glycolysis.

Krebs cycle

The cycle that oxidizes pyruvate to produce ATP, NADH, and FADH2 in the mitochondria.

Electron transport chain

The process that generates ATP through the transfer of electrons in the mitochondria.

Hydrogen reservoir

The intermembrane space of the mitochondria where hydrogen ions accumulate during cellular respiration.

Hydrogen reservoir

The area with the highest concentration of H+ ions, located in the intermembrane space of the mitochondria.

Nucleotides

Two nucleotides put together, held together by phosphodiester bonds and covalent bonds between the sugar and nitrogenous base.

Epinephrine

Hormone released by the adrenal medulla as part of the fight-or-flight response.

Loop of Henle

U-shaped part of the duct that connects the proximal convoluted tubule to the distal convoluted tubule.

Glomerulus

Renal artery in the above diagram.

Neuron

Basic unit of the nervous system.

Glial cells

Supportive cells in the nervous system.

Neurotransmitter

Chemical released from vesicles into the synapse to facilitate nerve signal transmission.

Postsynaptic membrane

Membrane that receives signals and binds neurotransmitter.

Synapse

Site where a neuron makes a connection with another neuron or an effector.

Post-transcriptional modifications

Changes to RNA molecules into mature RNA, including capping, tailing, and splicing.

Reflex arc

Simplest neural circuit that travels through the spinal cord and does not require coordination from the brain.

Cyclic photophosphorylation

Also known as the citric electron transport, it uses light energy to drive ADP to ATP and occurs in both aerobic and anaerobic conditions.

Action potential

Voltage difference across a nerve cell membrane when the nerve is excited, consisting of phases of depolarization, firing, peak, repolarization, undershoot, and stabilization.

Ammonia, urea, and uric acid

Waste nitrogens with different levels of toxicity and water requirements for excretion.

Hypertonic

Solution with a higher solute concentration than another solution.

Hypotonic

Solution with a lower solute concentration than another solution.

Genetic code

Specific coding relationship between bases and the amino acids they specify, expressed in codons.

Chargaff

Organic chemist who discovered the ratios of nitrogenous bases in DNA and proposed Chargaff's rule.