AP BIOLOGY: CELLS: FLASHCARD REVIEW
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-6phosphate.
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 highenergy 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 membraneDiffusion 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.