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4 levels of protein structure

primary structure
secondary structure
tertiary structure
quaternary structure

primary structure

linked series of amino acids with a unique sequence

secondary structure

polypeptides repeatedly folded and coiled

tertiary structure

overall shape of polypeptide resulting from interactions between the side chains of the various amino acids.

quaternary structure

overall protein structure that results from the aggregation on these polypeptide subunits

dehydration synthesis

The chemical process by which a molecule of water is removed from the reactants to join the reactants together.


Hydrolysis is a chemical process in which a molecule of a target substance is split into two parts by the addition of a molecule of water


motility structure present in some animal cells, composed of microtubules within an extension of the plasma membrane

endoplasmic reticulum

network of membraneous sacs and tubes, active in membrane synthesis and other synthetic and metabolic processed.. has rough ribosome studded and smooth regions


region where the cells microtubules are initiated , contains pair of centrioles.


reinforces cell shape , functions in cell movement , components made of proteings includes microfilaments, intermediate filaments, and microtubules.


organelle where cellular respiration occurs and most ATP is generated.. change energy to a form cells can use.


main brain of the cell


complexes that make proteins, free in cytosol or bound to rough ER or nuclear envelope.

golgi apparatus

active in synthesis , modification and sorting and secretion of cell products


produces hydrogen peroxide as a by product then converts to water


storage and breakdown of waste products , hydrolysis of macromolecules .


photosynthetic organele, converts energy of sunlight to chemical energy stored in sugar molecules.change energy to a form cells can use.


connect the cytoplasm for adjacent walls

cell wall

outer layer that maintains cells shape and protects form mechanical damage.

How are plant and animal cells different?

plant cells have a cell wall that made up of cellulose

eukaryotic cell

contains a nucleus

prokaryotic cell

no nucleus


speeds up a reaction without being consumed by a reaction

enzyme inhibitors

a molecule that binds to enzymes and decreases their activity

2 laws of thermodynamics

1st: energy in the universe is constant
2nd: energy conversions increase the disorder of universe

cellular respiration

bodes way of breaking down food molecules and making their strored energy available to the cell.

hydrogen acceptor

Any substance that is capable of becoming reduced and accepting hydrogen atoms, which allows the release of energy from such a reaction.

redox reaction

Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom, or ion.
Reduction is the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion.

how do autotrophs, heterotrophs and decomposers interact

Autotrophs (producers) are usually plants and synthesize their food with the help of sunlight. Heterotrophs are the organisms that feed on these plants(herbivores), or on the animals that are feeding on these plants(carnivores). these are collectively called as consumers. when all these producers and consumers die, the organic matter in their bodies are fed upon and thus broken down by decomposers. these thus release complex matter to simple forms which are again ready to be taken up by the plants. the cycle continues.

photosystem 1

is the second photosystem in the photosynthetic light reactions of algae, plants, and some bacteria.

photosystem 2

first protein complex in the Light-dependent reactions. It is located in the thylakoid membrane of plants, algae, and cyanobacteria. The enzyme uses photons of light to energize electrons that are then transferred through a variety of coenzymes and cofactors to reduce plastoquinone to plastoquinol. The energized electrons are replaced by oxidizing water to form hydrogen ions and molecular oxygen. By obtaining these electrons from water, photosystem II provides the electrons for all of photosynthesis to occur.

where does photosynthesis occur

Photosynthesis occurs in the chloroplasts (which contains the pigment Chlorophyll) of plant cells.

cyclic photoshphosphoryliation

produces energy needed for the reaction

non cyclic photoshphosphoryliation

produces NADPH and ATP for the dark reaction

internal system of chloroplast

The material within the chloroplast is called the stroma, corresponding to the cytosol of the original bacterium, and contains one or more molecules of small circular DNA. It also contains ribosomes; however most of its proteins are encoded by genes contained in the host cell nucleus, with the protein products transported to the chloroplast.

TEM image of a chloroplast
Within the stroma are stacks of thylakoids, the sub-organelles, which are the site of photosynthesis

light reaction

occurs in the sunlight

dark reaction

goes through a cycle and forms glucose with NADP+ and ADP being recycled back to a light reaction


enzymes,structure, receptors , transport

nucleic acid

information storage and transfer

how does flagella work

Flagella is a single tail, which is made from myosin and actin filaments, call it one mini muscle, that pushes the cell in one direction. A perfect example of this is Human sperm.


hey work to make reactions go faster in digestive and metabolic (energy related) processes. They are called 'catalysts' because they speed up the reaction by lowering the amount of energy needed to get the reaction started.


a chemical reaction which invloves breaking down complex molecules to simple substances.


reaction that breaks macromolecules into constituent individual subunits


It's a chemical reaction in which the standard change in free energy is positive.


Exergonic reactions are chemical reactions in which energy is released as heat.

how does light interact with the pigments in photosynthesis

Because they interact with light to absorb only certain wavelengths, pigments are useful to plants and other autotrophs --organisms which make their own food using photosynthesis. In plants, algae, and cyanobacteria, pigments are the means by which the energy of sunlight is captured for photosynthesis.

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