Chapters 4&5
What is the cell theory?
Cells are the basic units of life, all living organisms are made of cells, and all cells come from preexisting cells
What do anabolic pathways do?
They require energy and synthesize larger molecules
What are the three steps of cellular respiration (in order)?
Glycolysis, oxidation of pyruvate and citric acid cycle, and the oxidative phosphorylation.
What are photoautotrophs and give an example of one?
They use sunlight to make food. An example is plants, algae, and cyanobacteria
DNA is first transcribed into mRNA, mRNA strands are then translated into proteins.
What are two things that a plant cell has that an animal cell does not?
Cell wall, chloroplasts, a large central vacuole, and specialized plastids
What do enzymes do to activation energy?
They lower the activation energy thus speeding up the reactions
What is the total number of ATP generated by cellular respiration?
30-36 ATP per glucose molecule
What is the equation for photosynthesis?
6 CO2 + 6 H2O --> C6H12O6 + 6 O2
Explain codons and the genetic code
Nucleotides in an mRNA sequence code for amino acids in groups of 3 known as codons. There are 64 possible codons that code for the 20 amino acids and 3 stop codons.
What do both types of endoplasmic reticulum do?
the rough ER modifies proteins and the smooth ER synthesizes lipids
What are competitive inhibitors?
Plays a roll in enzyme inhibition, They have a similar shape to the substrate, competing with the substrate for the active site.
What is chemiosmosis?
The process of using kinetic energy from protons falling down its gradient to form ATP from ADP + Pi.
Where does the light reaction and the Calvin cycle take place?
The light reaction takes place in the thylakoid membranes of chloroplasts and the Calvin cycle takes place in the stroma of chloroplasts.
What are the three types of eukaryotic polymerases and what do each of them do?
RNA polymerase I: transcribes rRNA genes
RNA polymerase II: Transcribes protein-coding genes
RNA polymerase III: transcribes rRNA, tRNA, and small nuclear RNA genes
What three things affect membrane fluidity?
Define exergonic reactions
They are spontaneous reactions that occur without the addition of energy. The products of these reactions will have less free energy than the substrates.
What are the two types of fermentation and what happens in each.
Lactic acid fermentation: occurs in muscle cells, mammalian red blood cells, and some bacteria, when O2 is limited. And it turns pyruvate and NADH into lactate and NAD+.
Alcohol fermentation: happens in anaerobic yeast species and has two reactions. One turns pyruvate into acetylaldehide and the second one turns acetylaldehide and NADH into ethanol and NAD+
Explain what happens in the electron transport chains during the light reaction.
First, an e- is transported from PSII to PSI. Then the second transports e- from PSI to NADP reductase, the final e- acceptor of the night reaction is NADP+ which yields NADPH.
What do spliceosomes do?
They are protein complexes that take care of pre-mRNA splicing by recognizing sequences at the 5' and 3' end of the intron that is to be removed.
Explain hypertonic, isotonic, and hypotonic including what happens to a cell in each.
Hypertonic: the extracellular fluid has lower osmolarity than the cytosol- water leaves the cell so the cell shrivels.
Isotonic: the extracellular fluid has the same osmolarity than the cytosol- water does not move, nothing changes in the cell.
Hypotonic: the extracellular fluid has higher osmolarity than the cytosol- water enters the cell so the cell bursts or lyses.
Define endergonic reactions
When a chemical reaction requires an input of energy first. Products of these reactions will have more free energy than the substrates.
Where does each step of cellular respiration occur in the cell? (glycolysis, oxidation of pyruvate, Citric acid cycle, and oxidative phosphorylation)
Glycolysis: cytoplasm
Oxidation of pyruvate: mitochondria
Citric acid cycle: mitochondrial matix
Oxidative phosphorylation: inner mitochondrial membrane
What are the three stages of the Calvin Cycle? include what happens in each
Fixation: CO2 added to RuBP by enzyme Rubisco to generate 2 3-PGA molecules
Reduction: ATP and NADPH are used to add e- and make sugar (GA3P).
Regeneration: make more RuBP from GA3P
Explain the three steps of either translation or transcription to us.
Transcription: Initiation (promoter is a piece of DNA upstream that indicates where the RNA polymerase should bind and start), Elongation (RNA polymerase adds complimentary nucleotides to make the mRNA), Termination (liberates the mRNA strand, occurs by Rho protein interaction and formation of an mRNA hairpin, there are two types of termination signals: Rho-dependent and Rho-independent)
Translation: Initiation (mRNA attaches to the smaller subunit of the ribosome, AUG is the start codon- a tRNA with the appropriate anticodon attaches, the larger subunit of the ribosome then comes in) Elongation (tRNAs move in with the appropriate amino acid, the amino acid chain grows using peptidyl transferase), Termination (stop codon is reached, the amino acid chain then is processed (in Eukaryotes the amino acid chain moves into the endoplasmic reticulum to be further processed)).