Cells - Unit 1 Topic 1
Which type of cell has membrane bound organelles
Eukaryote
Name one factor the affects the reaction rate of enzymes
•Temperature
•pH
•Substrate and enzyme concentration
•Inhibitors
•Cofactors and coenzymes
How is oxygen transported around the body?
Blood
What is a pathogen?
An agent that causes disease?
Define Homeostasis
Homeostasis is the term used to describe a constant internal environment within a living organism despite internal or external changes.
Describe the function of mitochondria
Powerhouse of the cell. Cellular respiration occurs here to release energy for the cell to use.
What are the two methods of digestion?
–Mechanical [physical breakdown, e.g. chewing]
–Chemical [using enzymes]
What are the two types of cellular respiration?
–Aerobic respiration (needs oxygen)
–Anaerobic respiration (no oxygen)
What are the two parts of the immune system?
–Innate immune system
•Always working in all organisms
•Non-specific (reacts the same way for all pathogens)
–Acquired (adaptive) immune system
•Functions based on past exposure to pathogens
•Specific (reacts in a specific way for each pathogen)
Describe a negative feedback loop
When something is ‘wrong’, it’s adjusted back to optimal levels
Where is the site of protein synthesis
Ribosome
Name one difference between veins and arteries
Arteries:
Carry blood away from the heart. High blood pressure. Thick muscular elastic walls. Blood flows in pulses due to pressure from the heart and muscular walls.
Veins:
Carry blood to heart. Low blood pressure. Less muscular and less elastic. Blood flows smoothly. Valves prevent back flow.
Where does Aerobic respiration occur?
Mitochondria
What does the R0 measure?
R0 is a measure of the number of people who become infected by a single person with the disease.
Describe the function of Myelin Sheath in Nerves
Provides insulation for the axon and increases the rate of neural conduction
What are the 5 stages of Mitosis
Interphase, Prophase, Metaphase, Anaphase and Telophase
What are the 3 stages of Urine Formation
–Filtration
–Reabsorption
–Secretion
Where does Anaerobic Respiration occur?
cytoplasm
What are memory B and T cells?
These cells are formed during the first exposure to the pathogen and respond more quickly upon re-exposure by rapidly producing specific antibodies (B cells) and destroying infected cells (T cells), leading to faster clearance of the virus.
What are the three different types of Neurons
•Interneuron – Located in the CNS. Carry the signal from neuron to neuron. Some carry a message from sensory to motor neuron
•Sensory (afferent) Neuron – Part of PNS. Some include processes that act as receptors and detect change in the external or internal environment. All transmit sensory information from receptor to the CNS
•Motor (efferent) Neuron – Part of PNS. Carry signals from the CNS to the effector and causes it to respond
What is Osmosis?
The diffusion of water across a selectively permeable membrane, from an area of high concentration of water (hypotonic) to an area of low concentration (hypertonic), until equilibrium is reached (isotonic).
Describe the function of the Loop of Henle
Its main function is to reabsorb water and sodium chloride from the filtrate. This conserves water for the organism, producing highly concentrated urine.
What is the function of Xylem in plant cells?
Xylem cells transport water and minerals up
the stem from the roots to the shoots and
leaves. This transport occurs in one direction only.
A disease outbreak begins with 50 cases. After vaccination of 70% of the population, new daily cases drop significantly. Using this data, what can you infer about the mode of transmission and the effectiveness of the strategy?
The disease likely spreads through person-to-person contact, and the vaccine is highly effective, as herd immunity was achieved by reducing the number of susceptible hosts
Describe Kleptothermy
•Kleptothermy (stealing heat)
–Kleptothermy refers to the tendency of some organisms to share body temperature in order to stay warm – often occurs through huddling
–E.g. Emperor penguins huddle in the cold to share body temperature. This works similar to the idea of SA:V ratios – the lower the ratio, the less heat is lost