Biology Terms

hypertonic solution

(hyper, more than) lose water. Outside cell, the concentration of solute is more and the concentration of water is less, than inside the cell. Animal cells placed in hypertonic solution shrivel (crenate).

hypotonic solution

(hypo, less than) Cause the cell to gain water. Outside the cell, the concentration of solute is less, and the concentration of water is greater, than inside the cell.

Enzymatic proteins

Some plasma membrane proteins are enzymatic proteins that carry out metabolic reactions directly. Without the presence of enzymes, some of which are attached to the various membranes of the cell, a cell would never be able to perform the metabolic reactions necessary for its proper function.They are attached to a variety of membranes throughout the cell.

stroma

a double membrane surrounds a chloroplasts and its fluid filled interior. conversion of carbon dioxide to carbohydrate.

chlorophylls a and b

a pigment that can absorb various portions of visible light. Absorbs violet, blue, and red light better than the light of other colors.

carotenoids

a pigment that can absorb various portions of visible light. They are yellow or orange carotenoids that can absorb color in a violet, blue-green range.

exergonic reaction

a process that gives up energy such as cellular respiration

electron transport chain (ETC)

a series of carriers located in the thylakoid membrane that pass electrons from one to another.

methabolic pathway

a series of linked reactions.

grana

a stack of thylakoids

Receptor- mediated endocytosis

effective and much more efficient than ordinary pinocytosis. it involves receptors located in a location called the coated pit. A type of endocytosis

RuBP carboxylase

enzyme that speeds the Calvin cycle during the first phase. final stage of calvin cycle

reduction

gain of electrons

isotonic solutions

in which the cell neither gains nor loses water because the concentration of solute versus water is the same on both sides of the membrane.

Junction Proteins

involved in forming various types of junctions between cells. The junctions assist cell-to cell communication

G3P

is the product of the calvin cycle that can be converted to all sorts of organic molecules.

anchoring junctions

Are located in the heart, stomach, and bladder where tissue gets stretched. intercellular filaments attached to internal cytoplasmic deposits are held in place by intermediate filaments of the cytoskeleton.

Active transport

Molecules or ions move across the plasma membrane, accumulating on one side of the cell. It moves molecules towards higher concentration it needs a transporter and requires energy in order to move molecules against their concentration gradient.

Receptor proteins

Bind specific substances in the extracellular environment. They do not allow materials to cross the membrane.

CHAPTER 6

CHAPTER 6

chloroplasts

Carbon dioxide in the air enters a leaf through small openings called stomata. After entering a leaf cell, carbon dioxide and water diffuse into chloroplasts.

Carrier proteins

Carrier proteins are different from channel proteins because they can be either active or passive when transporting molecules across the plasma membrane. only allow specific molecules to cross the plasma membrane.

Cell recognition proteins

Cell recognition proteins are glycoproteins. Foreign cells bear their own glycoproteins that enable the immune system to recognize them and mount a defense. Without this recognition, harmful organisms ( pathogens) would be able to freely invade the body.

Facilitated diffusion

Certain molecules ( water, glucose and amino acids) and ions ( Na+,Cl-, Ca2+) cross plasma membranes at a rate faster than expected based o their size and polarity because their passage is facilitated. Requires a transporter but no energy.

Channel proteins

Channel proteins have a channel that, when open, allows molecules to simply move across the membrane. Always passive. play an important role in ATP synthesis.

Kinetic Energy

Energy in action

endergonic reactions

Energy must enter in order for these reactions to occur

Gap junctions

Form when two identical plasma membrane channels join. The channel of each cell is lined by six plasma membrane proteins. A gap junction lends strength to the cells, but it also allows small molecules and ions to pass between them. Utilized in heart muscle

Phagocytosis

Mobile like an amoeba able to engulf debris such as worn- out red blood cells or bacteria. A type of endocytosis

Bulk transport

Occurs when fluids or particles are brought into a cell by vesicle formation, called ENDOCYTOSIS, or out of a cell by evagination called EXOCYTOSIS. Cells can engulf large particles requires energy. Phagcytosis. Three types of endocytosis: Phagcytosis, Pinocytosis, Receptor-mediated cytosis.

Phospholipid bilayer

Or the plasma membrane in both eukaryotes and bacteria. Polar head of phospholipid is hydrophilic while the non-polar tails are hydrophobic.

sodium-potassium pumps

Proteins engaged in active transport. the pump undergoes a change in shape

ATP hydrolisis

Provides energy for muscle contraction.

Fluid- mosaic model

States that protein molecules embedded in the membrane have a pattern within in the fluid phospholipid bilayer.

Potential Energy

Stored Energy

Energy

The capacity to do work

Osmosis

The diffusion of water across the plasma membrane. Usually through proteins called aquaporin which are a type of channel proteins.

energy of activation

The energy that must be supplied in order to cause molecules to react with one another.

denatured

When an enzymes shape changes for factors such as high temperature or very low pH and then it can no longer bind its substrates efficiently.

photosystem II (PS II)

absorbs light with a wavelength of 680 nm

photosystem I (PS I)

absorbs light with a wavelength of 700 nm

thylakoids

absorption of solar energy. a different membrane system within the stroma forms flattened sacs called thylakoids, which in some places are stacked to form grana, so called because they looked like piles of seeds to early microscopists.

ATP

adenosine triphosphate. Releases a sufficient amount of energy with little waste. Its structure allows it to be coupled to an energy requiring reaction.

coupled reactions

are reactions that occur in the same place, at the same time, and in such a way that an energy-releasing (exergonic) reaction drives an energy-requiring (endergonic) reaction. Usually the energy- releasing reaction is the hydrolysis of ATP.

active site

binds the substrate(s) to form an enzyme-substrate complex. Has a shape that fit with specific subtrates

Photosynthesis

converts solar energy into the chemical energy of a carbohydrate

oxidation

loss of electrons

cofactors

many enzymes require the presence of an inorganic ion, or a non-protein organic molecule, in order to be active; these necessary ions or molecules are called cofactors. The inorganic ions are metals such as copper, zinc, or iron. The non-protein organic molecules are called COENZYMES.

differentially permeable

meaning that only certain substances can freely diffuse across the membrane and others cannot.

Diffusion

molecule moves from a high concentration to a low concentration until it is distributed equal.

Cholesterol

molecules are steroids present in animal cell membrane.

glycolipids or glycoproteins

molecules carrying carbohydrate chains. Both phospholipids and proteins can have them

competitive inhibition

occurs when the inhibitor and the substrate compete for the active site of an enzyme.

Pinocytosis

occurs when vesicles form around a liquid or around very small particles. Cells that use pinocytosis to ingest substances include white blood cells, cells that line the kidney tubules and the intestinal wall, and plant root cells. A type of Endocytosis

light reactions

only occur when solar energy is available

autotrophs

photosynthetic organisms, including plants, algae, and cyanobacteria, that produce their own organic food.

redox reaction

photsynthesis is indeed an oxidation- reduction, usually shortened to a redox reaction

tight junctions

plasma membrane proteins actually attach to each other, producing a zipper like fastening.

substrate(s)

reactants in an enzymatic reaction fit into enzymes like puzzle pieces, are binded into the active site

C4 plants

regions where temperature and rainfall tend to be hot and dry.

C3 plants

regions where temperature and rainfall tend to be moderate

Vitamins

small organic molecules that are required in trace amounts in the diets of humans and animals for synthesis of coenzymes. The vitamin becomes part of the coenzyme's molecular structure.

ATP synthase complexes

span the membrane and contain a channel that allows hydrogen ions to flow down their concentration gradient. the flow of hydrogen ions through the channel is a form of kinetic energy that alters the active site of the ATP.

calorie

the amount of heat required to raise the temperature of 1g of water by 1 degree celsius.

non- competitive inhibition

when an inhibitor binds to an enzyme at a location other than the active site. This is called the allosteric site. This causes the enzyme to be unable to bind substrates. You cannot fix this with adding excess amounts of substrates because the cell changes its shape. The process is usually reversible

induced fit model

when the active sight undergoes a slight change in shape to accommodate the substrate(s).

stomata

where air enters a leaf through small openings