Exam III Flashcards
List four functions of proteins in cells
- Enzymes that catalyze nearly all chemical reactions in a cell
- Proteins play structural roles acting as the cytoskeleton of cells and as membrane channels that allow molecules or atoms to pass into or out of the cell
- Some toxins made by disease-causing microorganisms are proteins
- Antibiotics made by the human immune system are proteins
Macromolecules that play structural roles acting as the cytoskeleton of cells and as membrane channels that allow molecules or atoms to pass into or out of the cell.
Proteins
Enzymes that catalyze nearly all chemical reactions in a cell are what type of macromolecule?
Proteins
Toxins made by disease-causing microorganisms are what type of macromolecule?
Proteins
Antibiotics made by the human immune system are what type of macromolecule?
Proteins
What type of macromolecule is used as membrane channels?
Protein
Give examples of five functions of proteins in eukaryotes and bacteria.
- Cytoskeleton
- Membrane channels
- Enzymes
- Toxins
- Antibodies
Define a “gene.”
A segment of DNA that codes for a protein or sometimes functional RNA.
What is a segment of DNA that codes for a protein or sometimes functional RNA called?
A gene
Define “gene expression.”
The process of turning the information in a gene into a functional product.
Consists of the processes of transcription and translation.
What is the process of turning the information in a gene into a functional product called?
Gene expression
What process consists of transcription and translation?
Gene expression
What are the two processes involved in gene expression?
Transcription and translation
When DNA is being accessed to code for a protein, what comes first: translation or transcription?
Transcription (“c” comes before “l” in translation)
Define DNA polymerase, focusing on its role in DNA replication.
- DNA polymerase, adds dNTPs to the 3’ end of the newly synthesized DNA chain.
- The dNTP added (either dATP, dTTP, dCTP or dGTP) is the one that base-pairs with the nucleotide on the template strand.
- DNA polymerase pauses every time it adds a nucleotide to double-check if the correct nucleotide is added. If the wrong nucleotide is added, it can “back-space” and cut out the incorrect nucleotide.
What molecules does DNA polymerase adds to the 3’ end of the newly synthesized DNA chain?
dNTPs
What type of protein is DNA polymerase?
An enzyme
What does dNTP stand for?
Deoxynucleotide triphosphate
How many types of dNTPs are there and what are they called?
There are 4 dNTPs:
- dATP (deoxyadenosine triphosphate)
- dCTP (Deoxycytidine triphosphate)
- dTTP (deoxythymidine triphosphate)
- dGTP (deoxyguanosine triphosphate)
What do dNTPs bind with?
dNTPs base-pair with the nucleotide on the DNA template strand as follows:
dATP –> Thymine
dTTP –> Adenine
dCTP –> Guanine
dGTP –> Cytosine
When does DNA polymerase pause?
Each time after it adds a nucleotide.
Why does DNA polymerase pause after each nucleotide added?
To double-check if the correct nucleotide is added.
What does DNA polymerase do if the wrong nucleotide has been added?
DNA polymerase can “back-space” and cut out the incorrect nucleotide.
Does DNA polymerase have a process to prevent the wrong nucleotide from being added to a new strand of DNA?
Yes. DNA polymerase can “back-space” and cut out the incorrect nucleotide.



















































