AS PAPER 2019 Flashcards
How is the DNA of a chloroplast different from nuclear DNA?
- DNA is shorter in chloroplasts
- DNA not associated with histone proteins
- DNA in chloroplasts is circular, Nuclear DNA is linear
Give one difference between the structure of a DNA nucleotide and the structure of an RNA nucleotide
Deoxyribose in DNA, ribose in RNA
Not all mutations in the nucleotide sequence of a gene cause a change in the structure of a polypeptide, give two reasons why
- genetic code is degenerate
- mutation may occur in an intron
State the uses of monoclonal antibodies
- targeting medication to specific cell types by attaching a therapeutic drug to an antibody
- detecting cancer cells (recognises receptor proteins on the surface of cancer cells and binds to them allowing the immune system to identify and destroy them)
- diagnosing HIV
- pregnancy tests
What is a monoclonal antibody?
Antibodies with the same tertiary structure and produced from a single clone of plasma cells
Describe the role of antibodies in producing a positive result in an ELISA test
- attach sample with potential antigens to well e.g blood sample
- add complementary monoclonal antibodies with enzymes attached
- wash well to remove unbound antibodies (to prevent false positives)
- add substrate -> enzymes produce products that cause a colour change in positive
Describe the test for non reducing sugars
- Do Benedict’s test and it stays blue / negative
- Heat in a boiling water bath with acid (to hydrolyse into reducing sugars)
- Neutralise with alkali (eg. sodium bicarbonate)
- Heat in a boiling water bath with Benedict’s solution
- Positive result = green / yellow / orange / red precipitate
Suggest a method to measure the quantities of reducing sugar in a solution
- filter and dry the precipitate
- find mass/weight
Explain why it is more useful to calculate an index of diversity than to record species richness
Index of diversity caculares how populated each individual species is within a community
Species richness only records how many different species in a given area
-> there may be many of some species, few of others
What is the correct order of these units: nanometre, metre, millimetre, micrometer?
Meter
Millimetre
Micrometer
Nanometer
Times or divide by 1000 to get to each
Name an organelle found in both a chloroplast and prokaryotic cell
70S ribosomes
What do N and n stand for in index of diversity?
N = total number of organisms of all species
n = total number of organisms of each species
