Final exam chapter 4 review Flashcards
Why is it important for a gene to have a specific sequence of nucleotides?
Because that sequence determines how the protein functions. And we need specific proteins to do certain functions for us to live and function properly
What is the definition of a gene?
A length of DNA that codes for proteins
List the basic steps in transcription and the end product. (3 phases)
Phase 1:
1.The hydrogen bonds between the bases in the DNA are broken and the histone is removed from the promoter
2. The complementary DNA strand separates and RNA polymerase binds to the promoter gene
Phase 2:
1. RNA polymerase gets the complementary bases that go together with the original DNA bases.
- At the stop signal the mRNA and the enzyme detach from the DNA strand and transcription ends
Phase 3:
1. The original DNA strands get back together
- RNA processes the newly transcribed mRNA and removes the introns and combines the exons.
- Then the mRNA leaves
List the basic steps in translation and the end product. (3 phases)
Phase 1 Initiation:
1. mRNA returns to the cytoplasm and binds to a ribosome
2. the ribosome reads the mRNA until it hits AUG (the start codon)
3. the tRNA anticodon UAC binds to the start codon
4. The P site in the ribosome is where the polypeptide building begins
Phase 2 Elongation:
1. Then another tRNA comes and brings more amino acids to the A site in the ribosomes
- Then the tRNA goes into the E site and exits the ribosome and is then able to be picked up again and create another anticodon
Phase 3 Termination:
1. this is where the ribosome reaches one of the three stop codons and the ribosome detaches and leaves the mRNA.
Where are triplets, Codons, and anticodons located?
Triplets- In DNA
Codons- mRNA
Anticodons- tRNA
What is a codon?
3 nitrogenous bases that code for the gene (the AUG stuff)
What is the difference between mRNA, rRNA, and tRNA and their functions?
mRNA- Carries the RNA template outside of the cell
rRNA- It reads the amino acids and links them together
tRNA- It delivers amino acids to the ribosomes
What is the function of RNA polymerase?
reading a DNA sequence and transcribing it into an RNA sequence
what are the three functions the Rough Endoplasmic reticulum do in respect to protein synthesis?
- Posttranslational modifications on proteins
- folding of proteins
- Sorting of proteins
What are the 4 benefits of using an enzyme in a chemical reaction?
- Increases the rate of the reaction (makes it go faster)
- Not changed by the reaction (can be used again
- Doesn’t change the nature of the reaction (it could’ve occurred without it)
- Lowers the activation energy
What does the enzyme isomerases do..?
It rearranges the atoms in a molecule
What does the enzyme hydrolase do? Name an example
It promotes hydrolysis
Example: adding water to sucrose to make glucose and fructose
What does the enzyme kinase do?
Adds a phosphate group
Why are kinases and phosphatases so important?
Because they act as the on and off switch for molecules. When kinases add a phosphate group it turns them on and activates them. But when phosphatases remove the phosphate group. Then it turns them off and shuts them down.
What is a zymogen and why are they important?
It is essentially an inactive enzyme that is activated when needed. A masking sequence stops the active site from being able to be seen and used.
IT is important because they keep the enzyme contained and prevent them from damaging other cells
What is an isozyme?
Where there are sugars that have the same chemical formula but they need different sugars to work on them and break them down
What does phosphatase do?
It removes phosphate groups
How does glucose remain in a cell against its gradient; what enzyme is responsible
It gets phosphorylated to create glucose-6-phosphate so it can’t go against the gradient. The enzyme responsible is Hexokinase
What is the purpose of the complexes in the electron transport chain?
When they move the electrons it makes energy. It then creates a proton gradient and pumps the free hydrogens in the cell to the outside of the cell. (complex 1,3, 4 and ATP synthase pump them across)
What is the basic steps of the citric acid cycle?
Pyruvate goes into citric acid cycle and converts to acetyl coA and binds with oxalacetate which makes citrate so we can continue to use it for energy
What is the purpose of NAD+ and NADH?
NAD+: to collect a hydrogen ion and take it to the electron transport chain (converts to NADH)
NADH: Goes to the electron transport chain to give proteins energy to make the Hydrogen gradient
What is the H+ gradient important?
To make energy to fuel ATP synthase
What does the enzyme Synthase do? Name an example
catalyzes synthesis reactions
Example: Synthase takes ADP and adds P to make ATP
How is ATP made during oxidative phosphorylation; what enzyme is responsible?
The ATP has a channel for the hydrogens to go with its gradient. Which then it gives the ATP synthase to phosphorylate and make ATP.
ATP SYNTHASE IS THE ENZYME RESPONISIBLE
