FLASHCARD REVIEW

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Glycogen

Glycogen is a polysaccharide and a polymer of glucose. It is like amylopectin but more extensively branched. Glycogen is stored in  liver and muscle cells in vertebrates. It is used for the storage of excess energy. When there is a demand for sugar, glycogen will break down through hydrolysis into glucose. Epinephrine stimulates the glycogen breakdown by activating glycogen phosphorylase. Glucose-1-phosphate is released which the cell later converts into glucose-6-phosphate.

Energy Transfer:  Draw a graph showing the effect of enzymes on an endergonic reaction.

The enzyme acts as a catalyst and lowers the activation energy.

Structure and Function: Describe an example of a structure-function relationship at the cellular level in animals.

Red blood cells are small and round, which allows them to fit through capillaries without clogging. They are also in the shape of biconcave discs, which maximizes the surface area of the membrane. This shape also makes the red blood cell flexible when passing through tight places.

Pinocytosis- "cell drinking", type of endocytosis in which the cell "gulps" droplets of extracellular fluid into tiny vesicles. It is not the fluid itself that is needed by the cell, but the molecules dissolved in the droplets. Because any and all included solutes are taken into the cell, pinocytosis is nonspecific in the substances it transports.

Phagocytosis- "cell eating", type of endocytosis in which the cell engulfs a particle by wrapping pseudopodia around it and packaging it within a membrane enclosed sac called food vacuole.The particle is digested after the vacuole fuses with a lysosome containing hydrolytic enzymes.

Glycolipid

Glycolipids are membrane components composed of lipids that are covalently bonded to monosaccharides or polysaccharides.

            Example: Red blood cells of O type blood have glycolipids containing Fucose, Galactose, N-            aceytlglucosamine, glucose, and a lipid tail in their plasma membranes.

Describe and diagram the regulation of calcium ion concentration in blood. (Regulation)

Calcium homeostasis refers to the regulation of the concentration of calcium ions in the extracellular fluid [Ca⁺⁺]_ECF. This parameter is tightly controlled because the calcium ions have a stabilizing effect on voltage-gated ion channels. The major regulator of calcium ions is the parathyroid hormone (PTH), which is part of a negative feedback loop to maintain [Ca⁺⁺]_ECF. PTH secretion is stimulated by hypocalcemia, and it works through three mechanisms to increase Ca⁺⁺ levels:

• PTH stimulates the release of Ca⁺⁺ from bone, stimulating bone resorption.
• PTH decreases urinary loss of Ca⁺⁺ by stimulating Ca⁺⁺ reabsorption.
• PTH indirectly stimulates Ca⁺⁺ absorption in the small intestine by stimulating synthesis of 1,25(OH)₂D in the kidney.

Explain the relationship between catabolic and anabolic reactions.

The sum of all chemical reactions within a living organism is known as metabolism. Catabolism refers to chemical reactions that result in the breakdown of more complex organic molecules into simpler substances—catabolic usually release energy that is used to drive chemical reactions. Anabolism refers to chemical reactions in which simpler substances are combined to form more complex molecules that can store energy—anabolic reactions usually require energy. The energy of catabolic reactions is used to drive anabolic reactions.

Chloroplast

·         Organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis.

Explain how energy coupling is used to drive endergonic reactions

·         Energy Coupling - the use of an exergonic process to drive an endergonic process

o   The free energy released from the exergonic process is absorbed by the endergonic process

·         Example:

o   Anabolic and catabolic processes are examples of how the cell couples reactions together to create efficient energy exchange cycles.

§  Catabolic reactions are those that convert chemical fuels to molecules that the cell can use for energy (ATP, other high-energy compounds)

§  Anabolic reactions are those that require some amount of energy to occur.

o   Cell can conveniently couple anabolic reactions with catabolic ones - the products of catabolic reactions can be used to drive anabolic reactions to completion. This allows the cell to link different types of reactions together efficiently

o    It's almost a type of "cellular recycling", as the products of one reaction (a catabolic one) can be re-used to help another reaction reach completion (an anabolic one)

Phagocyte

Phagocytes are cells that ingest and destroy foreign matter in a process known as phagocytosis. Phagocytes are a key element of the immune system. They possess high numbers of lysosomes. These lysosomes can engulf pathogens, debris, and dying cells. The lysosomes possess digestive enzymes that destroy englufed materials. On top of digesting particles, phagocytes have several other functions. They cause apoptosis, or programmed cell death. They are also instrumental in blood clotting and produce cationic proteins. Phagocytes are essential body cells for maintenance and defense of the body.

 

Describe and Diagram Chloroplast Structure

The chloroplast is surrounded by two layers of phospholipid membrane. An intermembrane space exists between the two layers. Chloroplasts contain their own DNA and ribosomes. The main units in chloroplasts are the thylakoids. Photosynthesis occurs in the thylakoinds, which are stacked into grana/crana. The thylakoids are surrounded by stroma, an aqueous liquid much like the cytoplasm. Lumen are the empty spaces inside thylakoids. Lamella link thylakoids from different grana. They are a system of membranes that contain chlorophyll.

 Exocytosis-  Exocytosis is the process by which a cell releases contents from inside itself to outside itself. The cell packages the materials, which are mostly proteins for secretion and wastes, into vesicles and ships them off to the membrane. The membrane-bound vesicles fuse with the cell membrane and sends its contents out of the cell. If the package contains proteins, it was shipped out from the Golgi Apparatus.

Pinocytosis-  Pinocytosis is essentially cellular drinking. In pinocytosis, the plasma membrane forms a dimple, so to speak, and the fluids outside the cell move into the space that was just created. Then the membrane extends out and closes off some of the fluids. The membrane that is enclosing the fluids pinches off from the rest of the membrane and goes into the cell. This newly formed vesicle now can go where the fluids are needed. Pinocytosis is a form of endocytosis that pays no attention to what else it brings in. Both phagocytosis and receptor-mediated endocytosis only bring in one object at a time. Pinocytosis brings in what it needs, but it also brings in whatever else was in the area. It is not particularly picky.

Phagocytosis - a type of endocytosis wherein a cell engulfs a large particle by engulfing it with pseudopodia

Cytochrome - an iron-containing protein that carries out election transport

Endocytosis- a process in which a substance gains entry into a cell without passing through the cell membrane. Endocytosis can be divided into three different types which include pinocytosis, phagocytosis, and receptor mediated endocytosis.

Describe the control of the movement of water across the cell membrane- water can cross a cell membrane through either a lipid pathway (water passes the lipid bilayer of the cell membrane by diffusion) or a water channel pathway (when the water cannot cross the lipid barriers, the water crosses these channels through either diffusion or filtration).

Describe the control of the movement of molecules across the cell membrane- Diffusion causes movement of molecules from a region of high concentration to a region of low concentration. This is how molecules move across a cell membrane.

 Receptor-mediated endocytosis:  a process by which cells internalize molecules (endocytosis) by the inward budding of plasma membrane vesicles containing proteins with receptor sites specific to the molecules being internalized.

Apoptosis: the process of programmed cell death (PCD) that may occur in multicellular organisms.[3] Biochemical events lead to characteristic cell changes (morphology) and death.

Osmosis:

    The movement of water molecules through a selectively permeable membrane to a solute with a higher concentration. When the cell is put into water, the molecules will pass through the membrane from a low concentration to a high concentration. Osmosis allows the necessary materials to enter the cells and leave out the waste. Whether the cell becomes hypotonic or hypertonic is determined by osmosis. If it is hypotonic then the cell will gain water by osmosis; if it is hypertonic then the cell will lose water by osmosis. An example of osmosis is the ability of plant roots to absorb water from the soil. Plant roots have a large surface area, therefore, water can enter the roots through osmosis.

Describe the three functions mitosis serves in multicellular organisms:

    Mitosis is used by multicellular organisms to replace old cells, repair damaged tissue, and make new cells for growth. Cells are constantly becoming worn out and damaged, therefore, it is necessary for multicellular organisms (such as humans) to quickly replace those cells as fast as they can before deterioration can occur.

Plasmolysis: A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs when the cell loses water to a hypertonic environment.

Heterochromatin: Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed.

TRANSPORT VESICLES: small membrane-bound organelles that carry secretory and membrane proteins in both directions between the rough ER and the Golgi complex and from the Golgi to the cell surface or other destination
GIVE AN EXAMPLE OF A COMMON SYNTHESIS ENZYME: RNA polymerase is involved in DNA synthesis by the process of transcription; enzymes that help simple sugars to form polysaccharides, amino acids to form proteins, and nucleotides to form nucleic acids

Cytoskeleton definition: a network of microtubules, microfilaments, and intermediate filaments that branch throughout the cytoplasm and serve a variety of mechanical, transport and signaling functions.

Cytoskeleton functions:

·         maintains cell shape

·         often protects the cell

·         enables cellular motion

·         plays an important role in intracellular transport

·         is very important in cell division forming the spindle fibers

Draw a graph showing the effect of enzymes on an endergonic reaction:

An enzyme catalyzes a reactant and lowers the amount of activation energy needed, chemical bonds weaken and reactions will proceed faster than without the catalyst.

Describe and diagram the regulation of  osmolarity of the blood

Osmolarity (the amount of solute per unit volume) is controlled by the nerve system when it senses a high concentration of salt ADH is released, which stimulates cells to release water into the blood stream lowering the salt concentration.

Glycocalyx

A carbohydrate rich coating found on eukaryotic and prokaryotic cells. Eukaryotic cell use this coating to regulate interior conditions and prokaryotic cells use it as a protective layer. It is most often associated with bacteria that cause infection.

Describe the regulation of genes in eukaryotes

The most common way for cells to regulate genes is through altering the rate of transcription. But cells can also alter the stability of mRNA molecules and altering the efficacy with which ribosome translate mRNA. 

The purpose of mitosis in single-celled organisms: In single-celled organisms, mitosis is a form of reproduction.  After the cell divides in mitosis, two exact copies of the organism exist.  This form of reproduction is asexual.  Mitosis only occurs in eukaryotic cells, so we're talking about single-celled eukaryotes.

Cytokinesis: The process in which the cytoplasm of a single eukaryotic cell is divided to form two daughter cells. It usually happens during the late stages of mitosis. It sometimes happens in meiosis if the cell is binucleate.  It is a different process that the prokaryotic binary fission.

Describe and diagram the structure of the mitochondria.

Answer: The mitochondria has a double membrane. The outer membrane is a simple phospholipid bilayer that contains proteins called porins that make the membrane permeable. Ions, nutrient molecules, and ATP are examples of substances that can pass through this membrane. The inner membrane is permeable to only oxygen, water, and carbon dioxide and has infoldings called cristae. The infoldings maximize the surface area of the inner membrane, which enhances the productivity of celluar respiration. The inner membrane divides the mitochondria into two compartments: an intermembrane space and a mitochondrial matrix. The matrix contains ribosomes, DNA

and enzymes.

The cytoplasm is a jelly-like substance between the cell membrane and nuclear envelope that holds all of the cell's organelles (except the nucleus). All of the contents in prokaryotic cells are contained within the cytoplasm. The function of the cytoplasm is to provide support and physical structure while also acting like a medium for transport inside the cell. The jelly-like substance allows organelles to "float" freely throughout the cell. It acts like a "molecular soup" where organelles are suspended and help together by a fatty membrane.

Describe the regulation of the cell cycle by cdks and cyclins:

Cyclins are regulatory subunits and CDKs are catalytic subunits of an activated protein; cyclins cannot perform catalytic activity and CDKs are inactive without a partner cyclin. When activated by a bound cyclin, CDKs perform phosphorylation that activates or inactivates target proteins to allow entry into the next phase of the cell cycle. Different cyclin-CDK combinations determine the different proteins targeted. CDKs must be expressed in cells whereas cyclins are made at specific stages of the cell cycle in response to different molecular signals. Different CDKs and cyclins work in different ways in various cells.

(These are really complicated...)

Describe how the physical properties of water contribute to thermoregulation in endotherms:

Since water has very high heat capacity, evaporation of the water in sweat removes heat and helps to cool body temperature. When water evaporates, the molecules with the highest energy escape from the group and into the atmosphere, leaving the molecules with the lower energy behind, i.e. cooling the endotherm to maintain a constant temperature (thermoregulation). (Endotherms are animals that regulate their body temperature from the inside, like mammals.)

*  knowing about evaporation helps understanding I think.)

Glycoprotein:

Glycoproteins are compounds in which a carbohydrate is covalently linked to protein. The carbohydrate content of these compounds varies: very little is found in collagens, for example, but glycogen in almost completely made of carbohydrate.

Glycoproteins are found in membrane-bound forms or in the intercellular matrix and in extracellular fluids. They are rare in bacteria.

Many glycoproteins are produced industrially by genetic engineering techniques to use as drugs.

Euchromatin: the less condensed form of eukaryotic chromatin that is available for transcription. The genes present in euchromatin is accessible to and can be used in the cell.

Structure and Function

Describe an example of a structure-function relationship at the organism level in animals.
The wings(structure) of bats and birds help them fly through the air(function). Their wings are lightwieght, smooth, and thin so air can glide over them.

Describe a function that requires the conformational change of a protein.
For active transport proteins, the sodium-potassium pump. The protein has a particular shape that has a high affinity to sodium ions so they can bind to it. When the ions fill the binding spots on the protein, the protein changes it shape to have a low affinity for sodium ions and, in turn, releases them, and now has a high affinity for potassium ions. The potassium ions now bind to the protein. The protein will continue to change shape as needed to either accept or release sodium or potassium ions.