Anatomy and Physiology – Cell Biology – Flashcards
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Replication
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The process by which DNA makes a copy of itself, occurs in nucleus 1) Helicase unwinds DNA strand and unzips it down the middle 2) DNA polymerase reads the unwound strands and lays down corresponding nitrogenous bases 3) Helicase zips strands back up and winds them into helix 4) Results in 2 identical DNA strands, half new, half old
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Cell Division
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The process by which a cell divides into two new daughter cells. Each daughter cell must be provided with a complete copy of the parental cell DNA
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Template Strand
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The DNA strand that provides the template for ordering the sequence of nucleotides in an RNA transcript.
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Complimentary Strand
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The DNA strand that is created by RNA transcript.
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Transcription
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(DNA-->mRNA) Process whereby the DNA sequence in a gene is copied into mRNA, occurs inside nucleus 1) Helicase unwinds and unzips new DNA strand 2) RNA Polymerase copies the DNA template into mRNA, replacing thymine with URACIL 3) mRNA leaves nucleus headed for a ribosome
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Translation
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(mRNA-->proteins) Process in which genetic information coded in mRNA codons direct the FORMATION OF SPECIFIC PROTEINS at a ribosome in the cytoplasm, occurs in cytoplasm 1) rRNA in the ribosome reads message from mRNA 2) tRNA brings amino acids that match mRNA codons 3) A chain of amino acid begins to form 4) The completed chain forms a protein
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mRNA
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messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome in the cytoplasm
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tRNA
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transfer RNA; type of RNA that carries amino acids to the ribosome -each tRNA is specific to an amino acid (20+)
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rRNA
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A globular RNA that is combined with special protein that makes up a ribosome -transcribed from DNA in nucleolus
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Codon
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A specific sequence of THREE adjacent bases on a strand of DNA or RNA -each codon provides genetic code information for ONE particular amino acid
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Gene
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A specific piece of DNA (series of codons) that codes for a specific protein which has a functional role in our life.
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RNA Polymerase
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An enzyme that links together the growing chain of RNA nucleotides during transcription, using a DNA strand as a template.
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Promoter
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A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA.
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Stop Codon
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The codon that ends all RNA translation (UAG, UAA, or UGA)
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Anticodon
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A sequence of three bases of a tRNA molecule that hydrogen bonds with the complementary three-nucleotide codon of an mRNA molecule during translation
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Mutation
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Any event that changes genetic structure of DNA/RNA
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Point Mutation
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mutation that affects a single nucleotide, usually by substituting one nucleotide for another
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Polysome
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A group of ribosomes moving along the same mRNA as they simultaneously translate it.
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Tay-Sachs Disease
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An inherited disease in which a DEFICIENTCY OF LYSOSOMES where glycolipid accumulation in brain neurons causes mental retardation, blindness and eventual death
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Free Ribosomes
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Ribosomes suspended in cytoplasm which will function in cytoplasm and not organelles (ex: enzymes)
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Lysosomes
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A membrane bound sack containing digestive enzymes that can break down macromolecules such as proteins, nucleic acids, and polysaccharides
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Rough Endoplasmic Reticulum
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System of internal membranes within the cytoplasm. Membranes are rough due to the presence of ribosomes. Functions in ASSEMBLY and TRANSPORT of PROTEINS to the golgi apparatus
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Secretion
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The process in which a functionally specialized substance is released from a gland or cell by EXOCYTOSIS
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Mitochondria
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An organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.
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Peroxisomes
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Abundant in the liver and kidney where they neutralize free radicals and detoxify alcohol and other drugs. Also break down fatty acids which mitochondria uses for energy.
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Cytoskeleton
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A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement
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Microfilaments
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-ACTIN Filaments (made of actin) -Long, thin fibers -Function in the MOVEMENT and support of the cell -Form MICROVILLI -7 nm external diameter (smallest)
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Intermediate Filaments
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-A component of the cytoskeleton that includes all filaments intermediate in size between microtubules and microfilaments -Most STABLE of cytoskeleton (make claws and hair) -Function in STRENGTH, stability, compartmentalization -Mechanical support for plasma membrane -12 nm external diameter (middle sized)
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Microtubules
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-Hollow rods composed of TUBULIN proteins -Form mitotic spindle during cell division -Play huge role in INTRACELLULAR MOVEMENT -make up part of the cytoskeleton -found in cilia and flagella -25 nm external diameter (largest)
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Flagella
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Plasma membrane extension specialized for locomotion, formed from a core of nine outer doublet microtubules and two inner single microtubules
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Cillia
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]Hair-like processes that project from epithelial cells -help propel foreign substances from the respiratory tract -made of microtubules
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Cellular Respiration
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Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
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Cellular Respiration
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-Takes place in mitochondria -Requires oxygen -Requires sugar (glucose) -Yields energy! (ATP) STEPS: Step 1) Glycolysis Step 2) Citric Acid Cycle Step 3) Electron Transport Chain
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Glycolysis
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Step 1 in Cellular Respiration -1 glucose molecule (6 carbon sugar) --> 2 pyruvate molecules -Does not produce much energy -Takes place in cytoplasm Yields: -2 Pyruvic Acid molecules -2 ATP
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Pyruvate
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-Broken down form of glucose -End product of glycolysis -Under aerobic conditions-breaks down to form acetyl CoA -Under anaerobic conditions-turns into lactic acid
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Pyruvate Oxidation
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Step 2 in Cellular Respiration (Transition Reaction Between Glycolysis and CAC) -Occurs in mitochondrial matrix Yields: -2 ACETYL COA molecules (initiators for CAC) -NADH -CO2
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Citric Acid Cycle
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Step 3 in Cellular Respiration -2 CA cycles for every 1 glucose molecule (one for each of the 2 pyruvic acid/Acetyl CoA molecules) -occurs in mitochondrial matrix 2 Citric Acid Cycles Yield: -2 ATP -4 CO2 -2 FADH2 -6 NADH
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Electron Transport Chain
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Step 4 in Cellular Respiration (Final Step) -Involves protein complexes embedded in mitochondrial membrane -Electrons captured from donor molecules and transported through these complexes -Hydrogen ions (protons) pumped outside of membrane, creating gradient -O2 --> H2O -ATP synthase uses this gradient to make 34+ ATP from ADP and phosphate
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ATP Synthase
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-A protein enzyme embedded in the membrane of the mitochondria -H+ ions move through ATP synthase as a result of facilitated diffusion -It makes ATP from ADP + inorganic phosphates
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Aerobic Respiration
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Respiration in which OXYGEN is CONSUMED and glucose is broken down entirely; water, carbon dioxide, and large amounts of ATP are the final products
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Anaerobic Respiration
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-ETC uses electron acceptors other than oxygen -Yields less ATP than aerobic resp
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Mitosis
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Cell's division of the nucleus. Final product is 2 daughter cells that are exactly like the parent cell.
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Proteasomes
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Function: Breakdown and recycling of damaged or abnormal intracellular proteins
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Metabolism
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All of the chemical reactions that occur within an organism
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Anabolism
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All synthesis reactions in a living organism; the building of complex organic molecules from simpler ones
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Catabolism
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Biological processes which primarily break down large storage and other chemicals, often releasing energy in the process.
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Plasma Membrane
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-A selectively-permeable phospholipid-bilayer forming the boundary of the cells -Separates cell contents from internal environment
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Cytoplasm
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A jellylike fluid inside the cell in which the organelles are suspended
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Microtubule
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A hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella.
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Centriole
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Formed from groups of Microtubules, form mitotic spindle during cell division
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Nucleus
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A part of the cell containing DNA and RNA and responsible for growth and reproduction
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Nucleoplasm
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The fluid contained within the nucleus of a eukaryote in which the chromosomes and nucleoli are found.
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Nucleolus
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A region within the nucleus where: -rRNA is transribed -ribosomes are partially assembled
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Chromosomes
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DNA molecules wraped around proteins and wound tightly
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Chromatin
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DNA and the proteins that it associates with. -Forms chromosomes -Site of mRNA synthesis
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Nuclear Envelope
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Double-membrane layer that separates nuclear contents from cytoplasm
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Nuclear Pores
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Openings in the nuclear envelope that control the movement of substances between the nucleus and cytoplasm -allow proteins to enter -allow mRNAs to exit
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Smooth Endoplasmic Reticulum
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Intracellular membrane system that functions in: -DETOXING of harmful substances -LIPID synthesis
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Rough Endoplasmic Reticulum
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An intracellular membrane system covered with ribosomes where many PROTEINS are assembled for: -secretion -lysosomes -plasma membrane
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Lysosome
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An organelle containing digestive enzymes -hydrolysis of macromolecules
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Golgi Apparatus
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A system of membranes that MODIFIES and PACKAGES proteins for export by the cell
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Mitochondria
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Organelle with both an outer and inner membrane, functioning in: -ATP energy synthesis -cellular respiration
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Ribosome
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Cytoplasmic organelle at which proteins are synthesized.
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Matrix
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The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the citric acid cycle.
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Cristae
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Infoldings of the INNER membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.
