Molecular Genetics and Homeostasis Flashcards

A set of flashcards based on lecture notes about Molecular Genetics and Homeostasis.

Antiparallel

Run in opposite directions, with one strand from 5’ to 3’ end and the other from 3’ to 5’ end.

Camp/Cap protein

Transcriptional activator protein in bacteria.

Chromosomal mutation

Involve large segments of DNA; types: deletion, duplication, inversion, translocation.

Codon

Sequences of three base pairs used to code for an amino acid.

Complementary mutation

A second mutation that restores function or balances the effect of the first mutation often by compensating for the original change.

Complementary base pairing

The specific pairing between nitrogenous bases in DNA and RNA, based on hydrogen bonding.

Deoxynucleotide

The basic building block of DNA.

DNA helicase

Enzymes that cleave bonds between nucleotides.

DNA ligase

Joins together Okazaki fragments.

DNA polymerase I

Removes the primers and fills in the space.

DNA polymerase III

Catalyzes the addition of new nucleotides.

Exon

Coding regions.

Frameshift mutation

Mutations that cause a shift in the reading frame (inserting or deleting 1-2 base pairs).

Gel electrophoresis

Used to provide genetic information to scientists in many different fields, separates the fragments based on size.

Gene expression

The process by which the information encoded in a gene is turned into a function.

Intron

Non-coding region.

Messenger RNA (mRNA)

Contains genetic information that determines the amino acid sequence of a protein.

Missense mutation

Results due to amino acid substitution and producing the wrong amino acid, may not always have an effect on the function of the protein.

Nonsense mutation

Substitutes a stop codon for an amino acid.

Nucleotide

The building blocks of nucleic acids.

Okazaki fragments

Lagging strand is synthesized discontinuously and is formed in short segments.

Operon

Genes are clustered in a region under the control of a single promoter.

Plasmid

Small circular double stranded DNA molecules found in bacteria.

Point mutation

Occur at a specific nucleotide in the genome, types: substitution, Frameshift (insertion and deletion).

Polymerase chain reaction

Used to amplify a specific segment of DNA.

Purine

Double ring structure (adenine and guanine).

Pyrimidine

Single ring structure (cytosine and thymine).

Restriction enzyme

Cut DNA only at specific sequences, usually 4-9 base pairs. Two types: sticky ends and blunt ends.

RNA polymerase

An enzyme that plays a central role in transcription.

Semi-conservative replication

The parent double helix produces two daughter double helices, each daughter molecule will have a parental strand and a daughter strand (an old strand and a new strand).

Taq polymerase

Binds to the double stranded DNA molecule at a promoter sequence.

Transcription

A DNA sequence serves as a template strand for the synthesis of RNA.

Transcription factors

Other proteins and molecules that bind to DNA and recruit RNA polymerase to begin transcribing that gene.

Translation

The second stage of gene expression, involves translating the nucleic acid code of mRNA into the amino acid code of a protein.

tRNA

Contains an anticodon that base pairs with a codon on the mRNA and has the corresponding amino acid attached to it, according to the genetic code.

Vector

A DNA molecule used to carry foreign genetic material into a host cell, where it can be replicated or expressed.

Miescher

Found nucleic acid from WBC, discovered nucleotide is made up of phosphorus and not sulfur.

Levene

Discovered ribose and deoxyribose, discovered the building blocks of nucleotides.

Avery

Ran tests on mice to discover that DNA contains the genetic code to be passed down through generations.

Chargoff

Discovered that A-T and C-G have to be equal, nucleotides have an equal amount of double ring and single ring structures.

Franklin

Photo 51, discovered the double helix.

Watson and Crick

Used all scientists data to discover the double helix with the phosphate and sugar as the backbone and the nitrogenous pairs bonded by hydrogen is what makes the rungs of the ladder. Realized that A-T and C-G are the only pairs that work.

5’ end and the 3’ end of DNA

The 5’ end has a phosphate group attached to 5’ carbon of the sugar and the 3’ end has a hydroxyl group on the 3’ carbon of the sugar.

Leading Strand

Strand that is synthesized continuously in the 5’ to 3’ direction.

Lagging Strand

Strand that is discontinuously synthesized in the 3’ to 5’ direction.

RNA Primers

They are needed for DNA synthesis because DNA polymerase III cannot begin the addition of new nucleotides without a RNA primer telling it where to begin.

Substitution

A type of point mutation when one base pair is replaced with another.

Insertion

A mutation when one ore more base pairs are added into the DNA sequence.

Deletion

A mutation when one or more base pairs are eliminated into the DNA sequence.

Chromatin Level

Controls access to DNA by modifying chromatin fibers (how tight the DNA is packed).

Transcriptional Regulation

Controls whether or not a gene is transcribed into RNA.

Post Transcriptional Factors

Controls the processing and fate of mRNA after it’s made.

Translational Regulation

Controls how efficiently mRNA is used to make protein.

Post-Translational Factors

Modifies proteins after they’re made.

Lac Operon

Negative control: the repressor binds the operator to block RNA polymerase, Positive control: involved CAP.

TRP Operon

Negative control: when tryptophan levels are low: repressor is inactive - can’t bind operator - operon is on - tryptophan is made.

Sticky Ends

Cuts that leave short, single stranded overhangs - useful for joining DNA from different sources.

Blunt Ends

Cuts that go straight through both strands, less sticky but still useful in cloning.

Sanger Sequencing

A method used to determine the exact order of DNA bases.

Action Potential

A rapid, temporary change in membrane potential that travels along a neuron, allowing nerve impulses to be transmitted.

Adrenal Gland

A gland above the kidneys that releases hormones like epinephrine, norepinephrine, cortisol and aldosterone in response to stress.

Automatic NS

A part of the peripheral nervous system that controls involuntary body functions.

Axon

The long extension of a neuron that conducts electrical impulses away from the cell body.

Bowman’s Capsule

Part of the nephron in the kidney that encases the glomerulus and collects the filtrate from the blood.

Central NS

Composed of the brain and spinal cord, processes information and coordinates body responses.

Control Centre

The part of the feedback systems that interprets input from the sensors and signals the effectors.

Counter-Current Flow

A system where fluids move in opposite directions to maximize exchange (i.e. in the loop of Henle to concentrate urine).

Dendrite

Branch-like extensions of a neuron that receive signals from other neurons and send them to the cell body.

Depolarization

Part of an action potential where the inside of a neuron becomes more positive due to sodium influx.

Distal Tubule

Part of the nephron that fine-tunes water, salt, and pH balance before urine enters the collecting duct.

Effector

Carries out the appropriate next step to keep system at homeostasis.

Filtrate

The fluid filtered from the blood into the Bowman’s capsule, containing water, ions, glucose, and waste.

Glomerulus

A capillary network in the nephron where blood is filtered into the Bowman’s capsule.

Homeostasis

The process by which a constant internal environment is maintained despite changes in the external environment.

Hormone

Chemical regulator or messenger, released by cells in one part of the body and affect cells in other parts of the body to speed up or slow down processes.

Hypothalamus

Part of the brain, serves as coordinating center, receives messages from monitors, initiates a hormonal/nervous response.

Interneuron

A neuron that connects sensory and motor neurons within the central nervous system to integrate signals.

Loop of Henle

Part of the nephron that creates a concentration gradient in the kidney to conserve water.

Myelin Sheath

A fatty layer around axons that insulates them and increases the speed of nerve impulse conduction.

Negative Feedback Loop

A mechanism by which an output is diminished; body works to reverse a change detected in a variable bringing it back to normal.

Neuron

A nerve cell that transmits electrical signals throughout the body.

Neurotransmitter

A chemical signal released by neurons at synapses to transmit messages to other neurons or effectors.

Node of Ranvier

Gaps in the myelin sheath where the action potential is boosted (saltatory conduction) in myelinated neurons.

Parasympathetic NS

The branch of the ANS that calms the body.

Parathyroid

Small glands near the thyroid that regulate calcium levels in the blood via parathyroid hormone.

Peripheral NS

All nerves outside the CNS, includes sensory and motor neurons.

Pituitary Gland

The master endocrine gland, located at the base of the brain, that releases hormones controlling other glands.

Positive Feedback Loop

Changes in conditions triggers response, the response serves to reinforce the change, far less common.

Protein Hormone

Made of chains of amino acids, soluble in water.

Proximal Tubule

The first section of the nephron where most reabsorption of nutrients, water, and ions occurs.

Reabsorption

The process in the nephron where substances are reclaimed from the filtrate back into the blood.

Receptor

Senses state of system.

Sensor

A structure that detects changes in internal conditions and sends signals to the control center.

Somatic NS

Part of the PNS that controls voluntary movement of skeletal muscles.

Steroid Hormone

Made from cholesterol, complex ring of H, C and O, soluble in fat but not water.

Sympathetic NS

The branch of the ANS that activates the “fight or flight” response.

Synapse

The gap between two neurons where neurotransmitters are released to pass signals.

Synaptic Cleft

The tiny space between the presynaptic neurons in the synapse.

Threshold Potential

The minimum voltage needed to trigger an action potential in a neuron.

Thyroid

An endocrine gland in the neck that releases hormones to regulate metabolism.