2015 Unit 2 Flashcards
What is the function of the coronary arteries
- Carry oxygen/glucose
* To heart muscle/ tissue/ myocytes
The rise and fall in blood pressure in the aorta is greater than in the small arteries. Suggest why.
Aorta • Is directly linked to the heart • Pressure is very high • Aorta has elastic tissue • Aorta has stretch/recoil
Give two ways in which the structure of starch is similar to cellulose
Both • Are polymers/polysaccharide • Contains glucose/carbon, hydrogen and oxygen • Contains glycosidic bonds • Have 1-4 links • Hydrogen bonding within structure
Give two ways in which the structure of starch is different from cellulose
Starch • Contains alpha glucose • Helical/coiled/compact/branched/not straight • 1,6 bonds • Glucose/monomers same way up • No H-bonds between molecules •No (micro) fibers/fibrils
Suggest and explain one other way in which sieve cells are adapted for mass transport.
- Few organelles
- Cytoplasm at the edge
- Hollow/ Large vacuole/ Large space/Thick walls
- More flow/ Thick strong walls resist pressure
Suggest and explain one other way in which companion cells are adapted for the transport of sugars between cells.
- Mitochondria releases energy/ATP/Site of respiration
- For active transport/uptake against concentration gradient
- Ribosomes/Rough Endoplasmic Reticulum produces proteins
- Proteins linked to transport eg. carrier proteins/ enzymes
Describe the role of DNA polymerase in DNA replication.
• Joins nucleotides (to form new strand)
Other than being smaller, give two ways in which prokaryotic DNA is different from
eukaryotic DNA.
Prokaryotic DNA
• Circular/non-linear DNA
• Not associated with proteins/ histones
• No introns
Humans and grasshoppers have very similar percentages of each base in their DNA but
they are very different organisms.
Use your knowledge of DNA structure and function to explain how this is possible
- Have different genes
- Triplets are in different order/sequence
- So different amino acid coded for/ different protein/different polypeptide/ different enzyme
The DNA of the virus is different from that of other organisms
Use your knowledge of DNA to suggest what this difference is. Explain your answer
Virus DNA
• A does not equal T/ C does not equal G
• So no base pairing
• So DNA is not doubled stranded/ single stranded
Give three ways in which courtship behaviour increases the probability of successful
mating.
- Recognise same species
- Stimulates release of gametes
- Recognition to opposite sex
- Indication of sexual maturity
- Formation of a bond between two organisms (to have young)
The events that take place during interphase and mitosis lead to the production of two
genetically identical cells. Explain how.
- DNA replicated
- Involving complementary base pairing
- Chromosomes line up along middle of the cell
- Sister chromatids are separated
- Each chromatid is separated to opposite poles
The student cut thin sections of tissue to view with an optical microscope.
Explain why it was important that the sections were thin.
- To allow more light through
* A single/ few layer(s) to be viewed
A mutation can lead to the production of a non-functional enzyme. Explain how
- Change/mutation in base sequence
- Change in primary structure (of enzymes)
- Change in hydrogen/disufide/ ionic bonds
- Change in tertiary structure
- Change in active site
- Substrate not complementary/ no enzyme-substrate complexes form
Explain why tumour area may not be the best indicator of tumour size and suggest a
more reliable measurement.
- Area does not take into account the depth
- Tumours are 3-D and not 2-D
- Measure tumour volume/mass/weight
