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146 Cards in this Set
- Front
- Back
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What is an endergonic reaction?
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A reaction in which energy is absorbed, such as photosynthesis.
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What is an exergonic reaction?
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A reaction in which energy is released,
such as cellular respiration. |
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What is anabolism?
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Building up
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What is catabolism?
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Breaking down
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What is metabolism?
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The sum of all anabolic & catabolic reactions in an organism or cell.
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What is an anaerobic process?
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A process that does not require oxygen.
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What is an aerobic process?
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A process that requires oxygen
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What are enzymes?
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Enzymes are protein catalysts that reduce the activation energy in a biological reaction. All chemical reactions require activation energy to break chemical bonds and begin the reaction.
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What conditions affect the function of enzymes?
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Very high temperatures may denature an enzyme due to the fact that enzymes are protein. Most pH levels will not affect the function of an enzyme.
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What is a substrate?
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A substrate binds to the active site of an enzyme to activate the enzyme so it can act as a catalyst.
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What is a competitive inhibitor?
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A competitive inhibitor is a substance that competes with an enzymes substrate for the active site on an enzyme.
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What is a non-competitive inhibitor?
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Non-competitive inhibitors do not compete at all. They bind to a site away from the active site, changing the shape of an enzyme so it no longer has an affinity for its substance.
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What is an allosteric site?
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A binding site some distance away from the active site that may bind to substances that may inhibit an enzymes activity.
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What is an activator?
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Activators bind to an allosteric site and stabilizes the protein conformation that keeps the active site available
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What is an allosteric inhibitor?
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An allosteric inhibitor binds to the allosteric site on an enzyme and activates the inactive form.
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What is feedback inhibition?
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A method of metabolic control when the product of a reaction comes back to an earlier part of a reaction and allosterically inhibits an enzyme.
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What is the function of dehydrogenase?
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Dehydrogenase removes hydrogen, electrons and energy. It is an exergonic process.
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What is the function of decarboxylase?
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Decarboxylase removes carbon dioxide and is an exergonic process
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What is the function of phosphorylase? Draw a diagram.
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Phosphorylase either adds/removes a phosphate or makes/uses ATP.
When ADP turns into ATP it is an endergonic reaction. |
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What are the 3 major steps involved in photosynthesis? Where do they occur?
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I) Capturing light energy in the thykaloid membrane
II)Light energy makes ATP + NADPH&H in the thykaloid membrane III) The calvin cycle making G3P in the stroma |
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Where does photosynthesis occur in prokaryotes?
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Photosynthesis occurs in the cell membrane folds in prokaryotes.
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Describe the structure of a chloroplast.
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Contained by an inner & outer phospholipid membrane
Material within called stroma Stroma is stacks of thylakoid disks Stacks are called grana Inside the disks is lumen Photosynthesis takes place in the thykaloid membrane, in the antenna complex with light absorbing pigments |
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Why is grass green? Explain the chlorophyll pigments.
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Chlorophyll A & B are the primary light absorbing pigments
They absorb photons of blue-violet and reg wave lengths Green is reflected |
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How does light energy travel?
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In wave packets called photons
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Explain the steps of the electron transport system.
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A group of photons strike photosystem II (p680)
A chlorophyll molecule gets excited and when it returns to ground state it releases energy The pathway is PQ > b6-f complex> PC > P 700 > fd > NADP reductase |
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How are electrons replenished?
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The Z protein breaks a water molecule
Electrons go into p 680 Oxygen is removed as waste H ions are released into the thykaloid membrane |
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What is the result of the H ions entering the thykaloid membrane?
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The H ions follow the concentration gradient and then move through ATP synthase which turns ADP + Pi = ATP
NADPH&H is created by 2 electrons 2 H ions moving through NADP reductase |
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What is non-cyclic phosphorylation?
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Involves both of the photosystems
As described "normally" |
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What is cyclic phosphorylation?
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Only involves photosystem I
Electrons are moved from the b6-f complex > PC > P700 > Fd > b6-f Generates ATP |
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Where does the calvin cycle occur and what are the three phases?
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Occurs in the stroma
I) Carbon fixation II) Reduction reactions III) RuBP Regeneration |
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Explain carbon fixation. What enzyme is involved?
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A CO2 molecule is added to a 5 carbon RuBP to form a 6c
Ribulose biphosphate carbolxylase splits the 6 carbon molecule into two 3 carbon molecules of PGA Occurs 6 times to make 1 glucose |
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Explain the reduction reactions.
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PGA is then phosphorylated into BPG using ATP
BPG is then reduced to G3P by using NADPH&H For every 1 G3P that leaves the cycle, 5 go on 2 x G3P = 1 glucose |
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Explain RuBP Regeneration.
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5 molecules of G3P must be converted back to 3 molecules of 5 carbon RuBP
There are 5 phosphates, 1/G3P & must end with 6, 2/RuBP 2 Pi are removed & 3 ATP are added 2 water molecules are added for the H & OH groups |
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What are the reactants & products of the electron transport system?
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Reactants: Light energy and water
Products: ATP + NADPH&H |
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What are the reactants and products of carbon fixation?
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Reactants: CO2 & a five carbon RuBP
Products: PGA (3-phosphoglycerate) |
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What are the reactants and products of
the reduction reactions? |
PGA + ATP > BPG & NADPH+H > G3P
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What are the reactants and products of RuBP regeneration?
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5 G3P, 3 ATP, Pi removed and water
Products: 3 five carbon RuBP's |
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What is cellular respiration?
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Cellular respiration is the conversion of energy trapped within glucose to energy available to do work within the cell in the form of ATP
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What is glycolysis and where does it occur?
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Glycolysis occurs in the cytoplasm
Glucose is broken down into 2 molecules of pyruvate by the addition of 2 ATP The breakage released 4 ATP NADH&H is also produced |
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What is the fate of pyruvate and why does this occur?
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NAD must be returned to the cell
This is done by removing pyruvate from NADH |
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What is ethanol fermentation?
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Ethanol fermentation is an anaerobic process and occurs in bacteria and yest cells.
pyruvate + NADH&H -> ethanol + CO2 + NAD |
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What is lactic acid fermentation?
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This is an anaerobic process and occurs in animal cells
pyruvate + NADH&H <-> lactic acid _ NAD When oxygen is available again, lactate is converted back into pyruvate so cellular respiration can continue |
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Explain oxidation of pyruvate.
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This is an aerobic process and occurs in the mitochondrial matrix of eukaryotic cells.
pyruvate + NAD + CoA-SH -> acetyl-CoA + NADH&H + CO2 occurs twice per cycle |
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What is the krebs cycle and where does it occur? Why is it cyclical?
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This process is aerobic and occurs in the mitochondrial matrix.
This process is cyclical because oxaloacetate is both a reactant and product 2 acetyl-CoA are produced/glucose |
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What happens if acetyl-CoA levels are high? Low?
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High: goes onto produce lipids
Low: Goes into the krebs cycle to produce more ATP |
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What is the ETC and where does it occur?
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This occurs in the inner membrane of the mitochondria. A set of oxidation-reduction reactions convert energy in FADH2 + NADH&H into ATP
NADH&H passes its electrons onto FADH2 because it cant fit in the membrane NADH dehydrogenase > Protein Q > cytochrome complex > cytochrome c > cytochrome oxidase complex > oxygen As the chain goes the molecules become more negative |
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What is chemiosmosis?
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Proton accumulate in the intermembrane space, creating an electrochemical gradient.
Protons want to move back across the inner membrane but cant due to the phospholipid by layer Enzyme ATP synthase distorts its shape to allow protons to move through it Once it goes back to its normal shape it is able to convert ADP + Pi > ATP |
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What is the ATP yield for NADPH, FADH2 and glucose
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NADPH: 3 ATP
FADH2: 2 ATP Glucose: 36 ATP |
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What steps of cellular respiration are aerobic?
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pyruvate oxidation
krebs cycle ETC |
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What steps of cellular respiration catabolic?
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glycolysis
pyruvate oxidation krebs cycle |
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What steps of cellular respiration are anabolic?
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The light reactions
The calvin cycle Glycolysis pyruvate oxidation krebs cycle ETC..kind of |
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Describe the structure of DNA. What is on the 5' end and what is on the 3' end?
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DNA is a polynucleotide
Each nucleotide consists of a pentose sugar, nitrogen base and phosphate. An OH is joined to the 3' and a phosphate is on the 5' |
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What does a phosphodiester bond hold together?
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A sugar and a phosphate
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What do the hydrogen bonds hold together?
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Two bases that hold the 2 polynucleotide chains together.
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What do glycosol bonds hold together?
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A sugar and a base
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What do 3 hydrogen bonds hold together?
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Adenine and Thymine
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What do 2 hydrogen bonds hold together?
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Cyostine and guanine
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Explain the 10 steps of DNA replication.
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1) DNA helicase unwinds DNA by breaking hydrogen bonds
2) DNA Gyrase further relieves tension 3) This creates a replication fork where the two strands seperate 4) ssB's keep the strands seperated 5) Primase creates a primer at the 3' end of the fork 6) Primer initiates polymerase synthesis of the complementary strand 7) DNA polymerase III adds the complementary bases in the 5'-3' direction 8) The leading strand is built continuously towards the fork while the lagging strand is built away in small okazagi fragments 9) DNA polymerase removes the primers 10) DNA Ligase attaches fragments by binding sugars and phosphates |
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Describe protein synthesis.
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DNA resides in the nucleus where it can not be harmed by cytoplasmic enzymes.
DNA has instructions to make proteins but ribosomes cant enter the nucleus So, DNA transfers its information onto RNA and RNA takes the info to the ribosomes in the process' of transcription and translation. |
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What is transcription? What are the four steps?
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Transcription is the process of making mRNA.. The 4 process' are initiation, elongation, terminate and post-transcriptional modifications.
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What happens during initiation?
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RNA polymerase binds upstream of the gene that is to be transcribed and the DNA unwinds.
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What happens during elongation?
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The template strand is used as RNA polymerase binds free floating nucleotides to their complementary bases. It moves in the 5' to 3' direction and mRNA hangs off of the side
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What direction is the template strand?
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3' - 5'
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What happens during termination?
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RNA polymerase reaches a terminator sequence, some time after the stop codons.
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What happens during post-transcriptional modifications?
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To further protect the mRNA from enzymes, A 5' cap is added and a poly-A-tail of ~ 200 adenines is added to the 3' end
In eukaryotes, splicesomes remove all introns and join the exons |
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What is translation?
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Translation is converting mRNA into protein.
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What are the 7 steps to translation?
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1) The 5' cap sticks to the ribosome
2) The mRNA moves through the ribosome 3) Each tRNA has an anticodon at its base that is complementary to the mRNA. It has an acceptor site at the 3' end where the amino acid is held. 4) The ribosome moves the mRNA until the AUG codon fits into to P site 5) Amino-acyl tRNA brings the amino acid to the A site 6) A peptide bond forms between AUG and the amino acid 7) This occurs until reaching a stop codon |
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What direction does mRNA run through the ribosome?
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5' to 3'
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Where is ATP used in protein synthesis? How?
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ATP is used to attach each amino acid to tRNA. This is done by enzyme amino-acyl synthases.
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How does DNA act as a template?
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DNA acts as a template because it is unwound by DNA helicase and then RNA polymerase reads it in the 5' to 3' direction.
URACIL IS ADDED INSTEAD OF THYMINE |
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What are ribosomes made of?
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Ribosomes are protein factories that are made of rRNA and protein. They are unable to enter the nucleus.
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Describe tRNA.
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tRNA is a cross like structure with an anticodon at its base.
At the 3' end there is an acceptor site that holds an amino acid. |
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What is a gene?
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A gene is a sequence of nucleotides in DNA that perform a specific function, such as coding for a protein.
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Name the differences between DNA and RNA in terms of:
Sugars, location, structure and bases. |
Deoxyribose vs. Ribose
RNA is found in the nucleus and cytoplasm, DNA is only found in the nucleus DNA is double stranded and long while RNA is single stranded and short RNA contains the base uracil instead of thymine |
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Describe the polymerase chain reaction
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The PCR allows DNA to be easily replicated
DNA is subjected to heat which breaks the hydrogen bonds and seperates the strands Synthesized lab primers are added The temperature is decreased to the primers can anneal to the 2 template strands Taq polymerase (an enzyme from bacteria) makes the complementary strands |
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Describe gel electrophoresis.
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Gel electrophoresis seperated DNA fragments using electricity.
Agarose gel is submerged in a salt solution that will conduct electricity DNA has a negative charge so the fragments move towards the positive end of the gel solution Smaller pieces move further DNA fragments are stained and then viewed under UV light This is a DNA fingerprint |
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What is homeostasis?
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The process of maintaining a constant internal environment despite changes in the external environment
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What is a feedback mechanism?
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A system in which part of the output of a system is connected back to the input.
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What is a coordinator?
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The part that detects and manages a response
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What is a regulator?
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The part that effects the change?
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What is the result?
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The effect of the regulator
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What is a negative feedback loop?
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A loop that is activated to restore an original condition, such as blood pressure.
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What is a positive feedback loop?
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A loop that is activated in order to amplify a small effect, such as birth contractions.
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What is thermoregulation?
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The maintenance of body temperature within a range that enables cells to function efficiently.
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Describe an ectotherm.
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An ectotherm is cold blooded and their metabolic activity is dependent on external temperature.
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Describe an endotherm.
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Endotherms are warm blooded and maintain a constant body temperature regardless of the external environment.
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What is the result of heat stress?
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Sweating: evaporation cools the surface of skin
Blood vessels dialate: More blood to the surface |
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What is the result of cold stress?
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Shivering: Muscle contractions make heat
Hair on end: Insulation Arterioles constrict: Blood stays in the center of the body |
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What are steroid and protein hormones made of? Which one is water soluble?
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Steroid hormones are made of cholesterol
Protein hormones are water soluble |
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Describe the pathway of a protein hormone.
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Protein hormones combine with a receptor on the cell membrane.
This activates the production of cAMP from the original ATP. cAMP acts as a messenger by activating existing proteins and enzymes |
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Describe the pathway of a steroid hormone.
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Steroid hormones circulate in the blood and then enter the target cell to bind to a receptor complex.
The hormone-receptor complex enters the nucleus and activates a gene, which causes transcription to occur |
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What is insulin?
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Insulin is a small protein hormone made in the pancreas
It is secreted when blood glucose levels rise for it makes cells permeable to glucose, making blood-glucose levels drop It is stored in the liver as GLYCOGEN, but then GLUCAGON converts it back to GLUCOSE when it is needed If an individual suffers from diabetes, they will have glucose in their urine and may be dehydrated because glucose is transported out of filtrate and water follows. If glucose is in the urine, water stays as well. |
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What are the goals of the kidneys?
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To remove urea and salts from the blood
To conserve glucose, amino acids, sodium and water Filter lots of blood Account for dietary changes Eliminate wastes |
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Describe filtration in the nephron.
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Blood from the renal artery travels to the afferent arteriol and then to the glomerulus
Pressure forces plasma and dissolved solutes through the membrane |
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What is the pathway for filtrate?
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proximal tubule, loop of henle, distal tubule, collection duct, renal pelvis,
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What is the pathway for blood?
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Efferent arteriole, capillaries, renal vein, vena cava
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What is reabsorbed in the proximal tubule?
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Actively: Glucose, amino acids, sodium
Passive: water, chloride due to hypertonic solution of sodium |
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Where else does water get reabsorbed?
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Everywhere except the ascending loop of henle
** Urea is absorbed in the collecting duct |
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What is a dendrite?
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The part of a neuron that receives messages
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Axon
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Carries nerve impulses away
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Synaptic Terminal
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The hair like ends of the axon
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Myelin Sheath
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Surrounds and insulates the axon
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The Node of Ranvier
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The gaps between the myelin sheath
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A Schwann cell
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Makes myelin
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What is a polarized membrane?
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K ions diffuse out of the neurone
Na ions diffuse into the neruon K ions diffuse more rapidly, and a positive charge assembles outside of the membrane |
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What is a depolarized membrane?
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When a nerve signals, the Na gates open and the Na ions rush into the nerve cell by charge attraction
This causes charge reversal Then the K gates open and K ions diffuse out of the nerve cell The action potential/voltage differences move across the membrane by this process |
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What is repolarization?
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The nerve membrane is repolarized by the pumps.
Every 3 Na that move out move 2 K in |
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Define the all-or-none response.
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A neuron is either on or off. A stronger stimulis does not produce a stronger result; only the sending of more signals.
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Describe a nerve synapse.
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A nerve synapse is a small space between neurons.
An incoming electrical signal causes vesicles to move to the end of the axon Vesicles release neurotransmitter molecules into synaptic cleft Neurotransmitters bind to receptors Signal in the dendrite is initiated |
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Describe an excitatory neurotransmitter
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Acetlycholine is released from vesicles
Eventually it binds to receptors and the complex causes Na ion channels to open Na ions rush into the post-synaptic neuron, causing depolarization Acetyl-cholinesterase is released and destroys acetylcholine |
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Describe an inhibitory neurotransmitter.
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A neurotransmitter causes post synaptic neuron to be permeable to k ions
The inside of the neuron is negative and thus hyperpolarized This prevents post-synaptic neurons from being active |
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Describe the first line of immune defense
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The skin acts as a barrier to pathogens
Lysozyme is an enzyme in tears that kills bacteria Acidic secretions prevent the growth of microbes Hair and mucous trap microbes Cillia filter microbes with their wave like motion |
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Describe the second line of immune defense.
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White blood cells, such as monocytes develop into macrophages and engulf microbes and then destroy them. Neutrophils engulf the microbe and then release enzymes to destroy itself and the microbe. (pus)
There is an inflammatory response due to increased blood flow. This results in swelling, heat and redness. There is also a fever so prevent bacteria from reproducing fast |
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Describe the third line of defense.
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Complement proteins are in the plasma and identify a microbe for phagocytosis or wrap it up or puncture its membrane
There is also lymphocytes |
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What do helper T cells do?
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Identify antigen markers
Release lymphokine which causes B cells to divide Pass on information to B cells |
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What do killer T cells do?
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Destroy infected or mutated cells in the body
Puncture the cell membrane |
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What do B cells do?
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Produce antibodies:
Antibodies increase the size of the microbe for phagocytosis OR bind to poisons and prevent them from attacking OR attach to viruses and change their shape |
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What do suppressor T cells do?
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Suppress the immune system after the microbe is killed
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What do memory B cells do?
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Carry and imprint of the microbe and alert B cells
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What is macroevolution? Provide an example.
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Macroevolution is large scale evolutionary change that is significant enough to warrant the classification of new groups into genera
This takes a long time from one common ancestor Darwins finches |
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What is microevolution?
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Changes in gene frequencies within populations that may result in the formation of new species
Takes less time Within a species Antibiotic resistance in bacteria |
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Why is Darwin important?
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Darwin developed the theory of natural selection.
Individuals of the same species compete Survivors pass on favorable traits Over time there is an accumulation of good traits For example, a leaf like praying mantis |
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Define evolution.
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Occurs when significant changes of inheritable traits of a species/population occurs over time
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What is a homologous structure?
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Similar structures doing very different functions.
Dolphin flipper and human hand |
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What is an analogous structure?
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Different structures doing very similar functions
Wings of a bird and bee |
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What is a vestigial structure?
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Structures with no function in one organism but function in another
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What is stabilizing selection?
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The extreme values for a trait are selected against
The mean stays the same The range is decreased |
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What is directional selection?
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One extreme is favored
Mean shifts up or down |
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What is disruptive selection?
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Both of the extremes are favored
Altered means and reduced ranges May be the development of new species |
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What is sexual selection?
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A trait that is selected that influences mating
Tend to be sexually dimorphic |
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What is the bottleneck effect?
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A large yet temporary reduction in population that may result in genetic drift (loss of alleles)
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What is the founder effect?
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A small population colonizes a new area causing a limited amount of alleles.
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What is gene flow?
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The opposite of genetic drift
Members switch colones to mix up alleles |
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What are prezygotic and postzygotic isolating mechanisms?
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Prezygotic: prevent mating or fertilization
Postzygotic: prevent development |
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What is ecological isolation?
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Two populations are in different geographical areas
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What is temporal isolation?
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Two populations are unable to exchange alleles because they are available at different times of the year or day
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What is behavioral isolation?
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Two populations do not respond to each others mating rituals.
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What is mechanical isolation?
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A physical barrier prevents fertilization
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What is gametic isolation?
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Chemical markers prevent an egg from being fertilized by the wrong sperm
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What is zygotic mortality?
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A zygote fails to develop to maturity
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What is hybrid inviability?
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The hybrid is born but does not live long
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What is hybrid infertility?
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The hybrid is healthy but is sterilized
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What is allopatric speciation?
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Two populations are geographically isolated prior to becoming separate species
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What is sympatric speciation?
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Two populations are in contact but stop exchanging alleles and become separate species.
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What is divergent evolution?
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When two or more species evolve very different traits due to different selective pressures
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What is convergent evolution?
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When two unrelated species become similar due to similar pressures
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