Upgrade to remove ads
Only $35.99/year

Biology Daily Questions and Answers Review

Terms in this set (22)

How does the structure of a phospholipid lead to the creation of a bilayer?
A phospholipid is composed of two parts; a hydrophilic (polar) phosphate head and two hydrophobic (nonpolar) lipid tails. This means that when phospholipids come into contact with water, they automatically bond together so that the tails are together and protected from the water and that the heads are facing outward, touching the water- this creates a bilayer, and it takes no energy to create it.
Are membrane proteins amphipathic? Why?
Yes, because amphipathic molecules have polar and nonpolar regions, and membrane proteins have to be amphipathic to form the bilayer, otherwise the proteins would be repelled by the phospholipids in the bilayer.
Compare and contrast diffusion, osmosis, and chemiosmosis.
Diffusion is the movement of molecules across a concentration gradient in the cell membrane. Osmosis is the diffusion of water across said membrane. And chemiosmosis a proton concentration gradient, the flow of which through ATP-synthase synthesises ATP. Diffusion, osmosis, and chemiosmosis are all forms of passive transport, so they require no energy and involve particles moving down its concentration gradient (from an area of high concentration to low concentration).
What is the difference between osmosis and water potential?
Osmosis is the movement of water from high to low concentration. Water potential is osmosis in plant cells, and it is basically osmosis with the addition of pressure (because plant cells cannot lyse, and so pressure builds up).
Nerve blockers prevent pain from being sent to the brain. They accomplish this by preventing a membrane potential from forming. How does this work?
They inhibit the sodium-potassium pump, which is how pain signals are sent to the brain (a membrane potential is a difference in charge inside vs. outside a membrane).
What would you say is the fundamental difference between the nervous system and the endocrine system?
The nervous system involves quick, rapid-fire, nearly instantaneous response due to local neurotransmitters. The endocrine system takes longer to activate due to its long-distance hormones, but its effects last longer, as hormones stay in the bloodstream for some time after they are released.
What are the two goals of cell communication?
Coordination (nervous system) and regulation (endocrine system) of activities within the bodies.
Compare and contrast a second messenger and a protein kinase.
Similarities: they both relay messages inside the cell.
Differences: one is a protein, one is not.
How do you change throughout your life?
Tastes, hair colour (greying), eye colour, allergies, thinning of the hair, skin, and nails, and various other developments occur due to the activation and inhibition of genes.
What are the three functions of the nervous system and what part of the nervous system performs them?
Sensory input, taking in information from the internal and external environments, is carried out by the peripheral nervous system. Integration/processing takes place in the central nervous system. Motor output, the sending of outgoing messages to affectors (usually muscles) uses the peripheral nervous system.
What is the primary function of the brain?
Processing/integration.
How do you learn?
The dendrites and terminal branches of your neurons grow and form more connections.
Compare and contrast the nervous and endocrine systems.
They both involve the release of chemical messengers into the body, but the nervous system uses local messengers known as neurotransmitters which are released into the synapses between neurons, whereas the endocrine system uses long-distance hormones that are released into the bloodstream and travel the entirety of the body. The nervous system deals in quick impulses and works quickly, but the endocrine system has a slower response and lasts longer as the hormones remain in the bloodstream after they are released.
How is a tropic hormone different from other hormones?
A tropic hormone has no direct effects on the body in terms of regulation, but it travels from one gland to another gland and tells the gland to release its hormones.
What are the components of a negative feedback loop? Provide an example of a hormone being used during negative feedback.
A negative feedback loop consists of a set point, some type of stimulus that pulls you away from the set point, and then a response pulls you back to the set point (usually involves the release of a hormone). One example is insulin, used to lower blood sugar levels to the normal set point.
What is the difference between nonspecific and specific defences?
Specific defences have personalised attacks for each specific type of disease. Nonspecific defence targets all foreign bodies the same way.
Compare and contrast the humoral and cell-mediated responses of adaptive immunity.
The humoral response uses B cells to form antibodies which remain in the bloodstream for long-term protection and the cell-mediated response uses cytotoxic T cells to kill antigen-infected cells immediately.
Why get vaccinated?
To build up adaptive immunity and produce antibodies to protect against antigen exposure.
How do you maximize the rate of exchange between an organism and the environment? Cell and bloodstream? What determines whether things diffuse in or out?
Surface area, and diffusion down a substance's concentration gradient.
Why do cells need to divide?
Growth (more cells), repair (replacing dead cells), and reproduction.
What is cancer? Ultimately, what causes cancer?
Cancer is when defective cells no longer adhere to checkpoints within the cell cycle and multiply out of control. It's caused by mutations in the DNA which affect the proto-oncogenes.
What is the hope for curing cancer?
Cancer-specific gene screenings and specialised treatments. As for cancer in general, natural killer cells and cytotoxic T cells show promise to hunt and kill cancer cells in the body.
Other sets by this creator