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Terms in this set (14)
structure of plasma membrane
membrane is made of phospholipid bilayer where the hydrophilic phosphate group faces the external surface and the cytoplasmic side of the cell. The hydrophobic, non-polar, fatty acid tails of the phospholipid molecule is sandwiched in between. The model to explain membrane structure is called the Fluid-Mosaic Model. According to this model, membrane is essentially fluid, like olive oil with proteins embedded in this fluid that gives it a mosaic appearance. Besides proteins, there are cholesterol molecules found in the membrane that give the membrane a little rigidity
different types of proteins that are associated with the membrane
Channel proteins, Carrier proteins, Cell recognition proteins, Receptor proteins, and Enzymatic proteins
Why is plasma membrane selectively permeable?
Because it allows only certain types of molecules to get across like small non-polar molecules, water, and gases. It does not allow charged molecules like ions, and large molecules.
How do molecules get transported across the membrane?
Two main mechanisms; Passive transport and Active Transport.
What are the two ways of passive transport?
Diffusion and Facilitated transport.
What are the energy requiring mechanisms of transport?
Active transport and transport of macromolecules by endocytosis and exocytosis.
What is osmosis?
the diffusion of water across a selectively permeable membrane due to concentration difference.
How are macromolecules transported into or out of the cell?
Endocytosis and Exocytosis. You should understand what these two processes are in detail
How is one form of energy converted to another in order for life to exist on the planet?
Plants convert solar energy to chemical energy in the form of carbohydrates. Animals depend on plants for their energy resources.
Conversion of one form of energy to another is never completely efficient. Most energy is lost in the form of heat energy. Cells convert one form of energy to another much more efficiently than most man-made machines!
How does carbon dioxide enter the leaves?
Through openings in the leaves called as stomata.
How do plants obtain water for photosynthesis?
Absorb water from soil which is conducted through vascular tissue from roots to other parts of the plant.
Photosynthesis involves two main reactions:
1. Light reaction: Dependent on light. Takes place in the thylakoid membrane of the chloroplasts. There are two types of light dependent reaction:
A. Non cyclic electron pathway: Requires PS II and PS I. PS II absorb light first and pass the electrons down the electron transport chain (Electrons are passed down the electron transport chain from one electron acceptor to the next) producing ATP. PS I absorb light and pass the electron to NADP molecule to form NADPH. Non cyclic pathway produces both ATP and NADPH. It is called non cyclic because the electrons released from photosystems never come back and instead passed to NADP molecule.
B. Cyclic electron pathway: Requires PS I only. PS I complex absorbs light, electrons travel down an electron transport chain (Electrons are passed down the electron transport chain from one electron acceptor to the next) producing ATP and the electron returns to PS I making the pathway cyclical. Cyclic pathway results only in ATP production.
2. Calvin Cycle: Also called as Dark reaction because it does not require light. Takes place in the stroma of the chloroplast. Calvin cycle utilizes atmospheric carbon dioxide to produce carbohydrates. This process requires ATP and NADPH that were produced during the light reaction. Calvin cycle has three steps: carbon dioxide fixation, carbon dioxide reduction and RuBP regeneration.
is the process of ATP production in the thylakoid membranes during photosynthesis. Chemiosmosis essentially involves movement of hydrogen ions (H+) across the thylakoid membrane along their concentration gradient from the thylakoid space towards the stroma along the channel provided by ATP synthase. ATP synthase utilizes the energy generated due to the movement of these hydrogen ions (H+) to synthesize or generate ATP.
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