June 2022 Flashcards
Describe the structure and function of the nucleus (4 marks)
Structure:
Nuclear envelope and pores
Double membrane and pores
Chromosomes/ chromatin
DNA with histones
Nucleolus
Function:
Holds/stores genetic information for polypeptides/ production
DNA replication
Production of mRNA , tRNA , transcription
Production of rRNA , ribosomes
Name of the main polymer found in plant cell walls and fungal cell walls
Plant: cellulose
Fungal: chitin
A reason that scientists use biomass instead of the number of individuals of each plant species when collecting data to measure diversity
Individual organisms can not be separated
Too small to count individuals
Too time consuming
Effects of farming on biodiversity
Plant biodiversity is LOWER on USED soil , diversity is HIGHER on land NOT used
Farming reduces biodiversity of fungi , reduces fungal species richness
How does the use of antibiotics lead to antibiotic resistant strains of bacteria in hospitals
Some bacteria have alleles for resistance
Exposure to antibiotics is selection pressure
Non resistant bacteria DIE , resistant SURVIVE
Patients have weak immune systems , more antibiotics used in hospitals
Disaccharide formed by 2 glucose molecules
Maltose
Aseptic techniques
Wash hands with soap
Sterilise pipette
Flame neck of bottle
Lift lid at angle
Sterilise spreader
Place pipette in disinfectant when done using
2 features that prokaryotic cells have that are not found in eukaryotic cells
No membrane bound organelles
Circular loop of DNA
Free DNA in cytoplasm
DNA not associated with proteins/ histones
How does the properties of a bilayer allow them to become positioned across the membrane
Hydrophobic side is next to fatty acid tails
Hydrophilic sides allow for the flow of ions through the membrane
When something is stained using monoclonal antibodies and viewed using a transmission electron microscope , what is the observations observed
Antibody binds
Antibody tertiary structure is complementary
Electron microscope has a high resolution
Describe viral replication
Attachment proteins bind to receptors
Nucleic acid enters the cell
Nucleic acid is replicated in the cell
Cell produces viral proteins
Viruses are assembled and released out of the cell
Describe the complete digestion of starch in a mammal
Hydrolysis of glycosidic bonds
Starch is converted to maltose by analyse
Maltose is converted to glucose by disaccaridase/ maltase
And enters the membrane bounds microvilli
Compare and contrast the structure of starch and the structure of cellulose
Both:
are polysaccharides ,
contain glycosidic bonds ,
contains hydrogen,oxygen, and carbon
Contrast:
Starch is alpha glucose and cellulose is beta glucose
Starch has a helical structure and cellulose is straight
Starch is branched and cellulose is unbranched
Cellulose has micro fibrils and starch does not
Describe transports of carbohydrates in plants
