Biology Paper 1 Flashcards
Explain how the counter-current principle allows efficient oxygen uptake in the fish gas exchange system
- Blood and water flow in opposite directions
- Concentration gradient maintained along length of lamella
Compare and contrast mitosis and meiosis
- Division of body cells
- results in 2 diploid daughter cells
- genetically identical
- used for growth, repair, and cell replacement
Meiosis:
1. germline cells divide into sex cells
2. 4 haploid daughter cells
3. genetic variation due to:
4. crossing over
5. random orientation
6. used for sexual reproduction
Similarities
1. Start as diploid cells
2. Same basic stages prophase, metaphase, anaphase, telophase
Qualitative Benedict’s Positive Test colour changes
Blue —> green —> yellow —> orange —> brick red
Active Transport
The movement of substances across a cell membrane through a carrier protein against a concentration gradient, from a low to high concentration with the expenditure of ATP
Describe and explain 3 features of starch that make it good storage molecule
- Insoluble in water so doesn’t affect water potential
- Branched alpha helix so makes molecule compact
- Branched for large SA for fast hydrolysis
Describe and outline 5 functions that proteins hold within an organism
- Structural: Keratin
- Enzymes: Pepsin
- Transport: Carrier and integral protein
- Hormones: ADH
- Antibodies
(Ultracentrifugation) Explain why the biologist used a blender and then filtered the mixture
- Break open cells and produce homogenate
- Remove unbroken cells and larger debris
Describe the processes involved in the absorption and transport of digested lipid molecules from the ileum into lymph vessels
- Micelles contain bile salts and fatty acids
- Make fatty acids more soluble in water
- Fatty acids absorbed by simple lipid diffusion
- Triglycerides reformed in cells
- Vesicles move to cell membrane
Species Richness
number of different species in a community
Facilitated Diffusion
the movement of molecules across a membrane with the assistance of a carrier protein
Describe and explain the effect of increasing carbon dioxide concentration on the dissociation of oxyhaemoglobin
- More oxygen dissociation
- By decreasing blood pH
Diffusion
passive movement of particles from a high concentration to a region of low concentration, down a concentration gradient
Factors affecting enzyme activity (4)
- Temperature
- pH
- Substrate conc
- Enzyme conc
Explain why it is more useful to calculate an index of diversity than to record species richness
- Index of diversity also measures population size of each species
- So useful because may be many of some species and less of others.
Monoclonal Antibodies
Antibodies produced from cloned plasma B lymphocytes
Non-Reducing Sugars
- Add 2cm³ of food sample then add 2cm³ of dilute HCl and heat.
- Add 2cm³ of NaHCO3 then do test for reducing sugars
Monomer
Smaller units from which larger molecules are made
Stages of response to a non-self antigen found in body fluid
- Ingestion (phagocytosis).
- Antigen Presentation.
- Clonal Expansion.
- Differentiation (T-cells and cell mediated immunity).
- Differentiation (B-cells and antibody mediated immunity)
Order of Organelles
Nuclei, Chloroplasts, Mitochondria, Lysosomes, Endoplasmic Reticulum, Ribosomes
What is the proteome of a cell?
The full range of different proteins that a cell is able to produce at a given time
Describe the role of one named organelle in digesting bacteria
- Lysosomes
- Fuse with vesicle
- Releases hydrolytic enzymes (lyzozymes)
Describe the fluid mosaic Structure
Fluid: All the components can move around.
Mosaic: Many different components all fit together
Explain how the chromosome number is halved during meiosis
- Homologous chromosomes pair
- One of each pair goes to each to opposite poles
Apart from mutation, explain one other way genetic variation within a species is increased
- Random fusion of gametes
- Produces new allele combinations
Co-Transport
- The simultaneous transport of two different substances through one carrier protein.
- One substance (usually an ion) moves down its concentration (passive) whilst the other substance is transported against its concentration gradient (active transport)
Antibody
A protein molecule that can bind specifically to an antigen
Test for Lipids
- Mix Test solution with ethanol.
- Shake for 1 minute then add water.
- Cloudy white emulsion
Pulmonary Ventilation
Tidal volume x Ventilation rate
Cardiac Output
stroke volume x heart rate
Describe the roles of micelles in the absorption of fats into the cells lining the ileum
- Micelles include bile salts and fatty acids.
- Makes fatty acids more soluble in water
- Brings fatty acids towards the lining
- Fatty acids absorbed by diffusion