Unit 2 Short Answer Flashcards
Differences between plant and animal cells
Plant cells have chloroplasts, vacuoles, and a cell wall while the animal cells do not. Animal cells have a centriole and lysosome whereas plant cells do not.
Plant cells are usually more rectangular and animal cells are more circular.
Hypertonic, hypotonic and isotonic solutions
Hypertonic is when the concentration of solute molecules outside the cell is higher than inside the cell (in the cytosol). So the solution outside is hypertonic to the cytosol. H20 moves out of the cell, cell shrivels.
Hypotonic is when the concentration of solute molecules outside the cell is lower than inside the cell (in the cytosol) so the solution outside is hypotonic to the cytosol. H20 moves into the cell, cell gets harder or firm and could burst.
Isotonic is when the concentrations of solute molecules inside and outside the cell are equal. Water diffuses into and out of the cell at equal rates. H20 moves in and out.
Mitochondria and energy requirements of different cells
Mitochondria are needed more in places such as muscle and brain cells because they produce more energy. Anywhere that needs lots of energy is where mitochondria is most needed.
Prokaryotes go through with anaerobic respiration and only need two ATP because they are single celled.
Eukaryotic cells and other multicell organisms need much more energy because they are much bigger.
Differences between photosynthesis and cellular respiration
Photosynthesis is a complex set of chemical reactions, in which the product of one reaction is consumed in the next reaction. This is also known as a biochemical pathway. Cellular respiration is a complex set of chemical reactions in which some of the energy stored in organic compounds is released. The chemical equations for the two processes are opposite.
Function of a sodium-potassium pump
Nerve cells (neurons) need to have a higher concentration of potassium ions inside and a lower concentration of sodium ions outside than in the fluid outside the cell. To do this the pump moves ions from an area of low concentration to an area of high concentration. The sodium-potassium pump uses ATP to pump 3 sodium out, and pump 2 potassium in.
Chemical equations for photosynthesis and respiration
Photosynthesis:
CO2 + H2O + light energy -> organic compounds + O2
Cellular respiration:
organic compounds + O2 -> CO2 + H2O + energy
Differences between active and passive transport
Active transport: drives molecules across a membrane from a region of lower concentration to a region of higher concentration or against a concentration gradient. This process requires energy.
- carrier proteins that require energy are called pumps.
Passive Transport: The movement of molecules across a cell membrane without energy input from the cell. The molecules will move from an area of high concentration to an area of low concentration. This can also be referred to as moving down the concentration gradient.
Active transport requires energy for the movement of molecules whereas passive transport does not require energy for the movement of molecules.
In active transport, the molecules move against the concentration gradient and expend energy whereas in passive transport, the molecules move along the cell membrane and don’t use any energy.
Actin and Spindle fibres – roles
Actin are thin fibers that are pulled to cause muscle contraction. Spindle fibers are thick enough to be visible by a light microscope, they assist in the movement of chromosomes during cell division.
After cell division is completed the spindle fibers disassemble and become microtubules again.
Cellulose – what kingdoms it’s found in, role in diet
Cellulose is a polysaccharide and is apart of the plantae kingdom, it aids digestion of other nutrients by helping to push the food through the intestines
Why vegetation gets brown and limp in the spring
Vegetation gets brown and limp in the spring because the salt makes the outer environment of the vegetation hypertonic, so the water leaves the vegetation and causes plasmolysis making the vegetation brown and limp.
