Random Biology 🧬🧫 Flashcards
Suggest why log scales are used in biology (1 mark)
Large range of data
Explain how the second messenger model of glucagon works (5 marks)
- Glucagon binds to receptors on liver cell membrane
- This causes a change in the shape of the enzyme adenylate cyclase, activating it
- This enzyme converts ATP into cAMP
- cAMP activates kinase
- Which catalyses the hydrolysis of glycogen into glucose
Explain how the second messenger model of adrenaline works (5 marks)
- Adrenaline binds to receptors on liver cell membrane
- This causes a protein (G protein) to be activated
- This enzyme converts ATP into cAMP
- cAMP activates kinase
- Which catalyses the hydrolysis of glycogen into glucose
State the first and second messengers in the second messenger model of glucagon (2 marks)
- First: glucagon
- Second: cAMP
Describe how a low blood glucose concentration is detected (3 marks)
- Detected by alpha cells
- In the Islets of Langerhans
- In the pancreas
State where glucagon and insulin are secreted from (1 mark)
Pancreas
State where adrenaline is secreted from (1 mark)
Adrenal glands
Describe how a high blood glucose concentration is detected (3 marks)
- Detected by beta cells
- In the Islets of Langerhans
- In the pancreas
Suggest how you would ensure that data is representative (2 marks)
- Random samples
- Large sample
DNA –> mRNA (1 mark)
Transcription
mRNA –> tRNA (1 mark)
Translation
Explain what a P value of less that 0.02 suggests (2 marks)
- Probability that difference is due to chance is
less than 0.05 - Reject null hypothesis
Polymer in cell walls of plants (1 mark)
Cellulose
Polymer in cell walls of prokaryotes (1 mark)
Murein
Polymer in cell walls of algae (1 mark)
Cellulose
Polymer in cell walls of fungi (1 mark)
Chitin
Things to look out for when evaluating conclusions (6 marks)
- Stats test
- Sample size
- Humans or animals?
- Other factors involved
- Correlation does not mean causation
- STDs + significance
State the location of chemoreceptors and baroreceptors (1 mark)
Aorta
Name three monosaccharides (3 marks)
- Glucose
- Galactose
- Fructose
State some properties of glycogen which make it suitable for its functions (3 marks)
- Branched (for quick hydrolysis of enzymes)
- Insoluble (so not affected by water potential)
- Compact (good storage)
State the number of water molecules produced during the formation of triglycerides (1 mark)
3
State and explain the properties of triglycerides, relating them to their function (8 marks)
- Energy storage
- -> Large ratio of energy storing C-H bonds compared to the number of C atoms
- Metabolic water source
- -> High ratio of H to O atoms so if oxidised, they release water
- Do not affect water potentials and osmosis
- -> Large and hydrophobic, so insoluble in water
- Good storage molecule
- -> Low mass so doesn’t make animal more heavy
Explain how enzymes lower the activation energy of a reaction (3 marks)
- Active site is induced / slightly changes shape to mould around the substrate
- When the E-S complex forms, the enzyme moulding puts a strain on the substrate’s bonds, weakening them
- This lowers the activation energy
State the molecules which form ribosomes (2 marks)
- RNA
- Proteins
State the function of RNA (1 mark)
Transfers genetic information from DNA to ribosomes
State the sugar in a nucleotide (1 mark)
Deoxyribose
Where are phosphodiester bonds formed (1 mark)
Between 2 nucleotides
State the roles of each of the following ions in the body: - Hydrogen ions - Iron ions - Sodium ions - Phosphate ions (8 marks)
Hydrogen ions
- Lowers pH of solutions
- Could impact enzyme / haemoglobin function
- Involved in chemiosmosis
Iron ions
- Component of haemoglobin in the transport of oxygen
Sodium ions
- Involved in the co-transport of glucose and amino acids during absorption
- Plays a role in generating action potentials
Phosphate ions
- Component of DNA (phosphodiester bonds)
- Component of ATP
Function of Golgi vesicles (1 mark)
- Store proteins and lipids made by Golgi Apparatus and transport them around the cell
Function of Golgi Apparatus (1 mark)
Processes + packages proteins and lipids made in the rough ER
Function of vacuole (1 mark)
Absorbs water by osmosis and swells, keeping the cell rigid
When are chromosomes visible in a cell (1 mark)
When they are condensed
Length of stage micrometer (1 mark)
100 micrometers
Structure of endoplasmic reticulum (2 marks)
- Both rough and smooth have folded membranes called cisternae
- Rough has ribosomes on the surface
Structure of golgi apparatus (2 marks)
- Folded membranes make cisternae
- Vesicles on the surface of cisternae
Function of golgi apparatus + vesicles (3 marks)
- Adds carbs to proteins to form glycoproteins
- Produces secretory enzymes
- Transports modifies + stores lipids
Function of RER + SER (2 marks)
RER - Site of protein synthesis
SER - Synthesises stores lipids + carbohydrates
Function of lysosomes (3 marks)
- Involved in phagocytosis
- Break down dead cells
- Digest worn out organelles for reuse of materials
Describe the structure of mitochondria (4 marks)
- Double membrane
- Inner membrane called the cristae
- Fluid centre called he mitochondrial matrix
- Loop of mitochondrial DNA
Explain why the determination of dry mass is an appropriate method to use to compare growth of plants (2 marks)
- Determines increase in organic material
- Water content varies
