Pp Questions Flashcards
Describe the primary structure of all proteins.
A sequence of amino acids joined by peptide Bonds
This question is about genetic code.
Define universal, non-overlapping, degenerative
Universal= The same codon always codes for the same amino acid.
Non-overlapping= Each base is only part of one codon
Degenerate= Morethan one codon for each amino acid
Describe one difference between the structure of DNA in a prokaryotic cell and in a eukaryotic cell.
In prokaryotes…
DNA is circular NOT linear
Has no introns
Describe 2 differences between the structure of triglycerides and phospholipids.
Triglycerides….
3 Easter bonds rather than 2
No phosphate group
3 fatty acids rather than 2
Explain why phospholipids can form a bilayors but triglycerides cannot. (3 marks)
Phospholipids are polar
OR
Have a hydrophilic and hydrophobic end,
Phosphate group is charged,
So attracts water.
Triglycerides are hydrophobic.
Describe the role of tRNA in translation. (2 marks)
Anticodon binds to codon,
Brings specific amino acids
Describe how gas exchange occurs in single-celled organisms and explain why this method cannot be used by large, multicellular organisms.
Diffusion across cell surface membrane.
Large organisms have a smaller SA:V ratio
So diffusion pathway would be too long.
Name two enzymes that are involved in replicating the DNA of a virus and describe their roles in the replication process.
DNA helicase breaks hydrogen bonds
DNA polymerase joins adjacent nucleotides via condensation reaction
A student prepared a plant route to observe cells undergoing mitosis
He put the root into a small bottle of hydrochloric acid in a 40 degrees water bath.
Why did he put the plant root in acid?
Breakdown the cell wall
Describe the mechanism for the absorption of amino acids.
Facilitated diffusion of amino acids. Co transport sodium ions actively transported from cell to blood creating a conc gradient. Facilitated diffusion of amino acids into blood
Give the two types of molecules from which a ribosome is made.
RNA
Protein
Give 4 structural differences between a DNA molecule and mRNA.
DNA = double stranded, thymine, deoxyribose, hydrogen bonds.
mRNA= single stranded, uricil, ribose, no H bonds
The resolution of an image obtained using an electron microscope is higher than the resolution of an image obtained using an optical microscope.
Why?
Shorter wavelength between electrons in electron microscope. Longer wavelength of light in optical microscope.
Name 2 structures found in all bacteria that are not found in a plant cell.
70s ribosome
Murein cell wall
Circular DNA
Name 2 features of HIV particles that are not found in bacteria.
Not include attachment protein
Capsid
Envelope
RNA genome
Reverse transcriptase
What is a tumor?
Mass of cells with uncontrolled cell division
Describe how you would determine a reliable mitotic index from tissue observed with an optical microscope.
Do not include details of how you would prepare tissue to be observed with an optical microscope.
Count cells in mitosis in the field of view,
Divide by total number of cells in field of view
Repeat for random fields of view
Explain why giving children more than one tetanus vaccine develops good immunity.
More memory cells so higher conc of antibodies.
