World of the Cell chapter 4

Nucleus of Euk cell

Cytoskeleton

A network of microtubules, microfilaments, and intermediate filaments that branch throughout the cytoplasm and serve a variety of mechanical and transport functions

Eukarotic Chromatin

50% proteins that include lots of his tone proteins and 50% DNA

Exocytosis

the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out.

Endocytosis

The cellular uptake of macromolecules and particulate substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle.

Centrioles

One of two tiny structures located in the cytoplasm of animal cells near the nuclear envelope; play a role in cell division

Chromosomes

Don't exist in bacterial cells. Contains as much histone proteins as DNA. where DNa is packaged , segregated during cell division and transmitted to daughter cells.

Cristae

(plural, cristae) An infolding of the inner membrane of a mitochondrion that houses the electron transport chain and the enzyme catalyzing the synthesis of ATP. increases surface area

Inner and Outer mitochondrial membranes

encode some of the RNA proteins needed, along with ribosomes involved in protein synthesis

Mitochondria matrix

the fluid that in inside the inner membrane of the mitochondria, where Krebs cycle takes place

Mitochondria

came from bacterial cells. organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use. Have there own DNA comes from maternal genes.

Mitochondrial Disorders

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Chloroplast

5 to 10 micrometers long. Surrounded by a inner and outer membrane. , organelle found in some plant cells and certain unicellular organisms where photosynthesis takes place.Maternal inheritance

Thylakoids

Photosynthetic membranes contained in the chloroplast where chlorophyll and other pigments are located. The light dependent reactions of photosynthesis take place here. A flattened membranous sac inside a chloroplast. Thylakoids exist in an interconnected

stroma Thylakoids

membranes that interconnect the thylakoids

Granum

(plural, grana) A stacked portion of the thylakoid membrane in the chloroplast. Grana function in the light reactions of photosynthesis.

Plastids

group of plant organelles that are used for storage of starches, lipids, or pigments, organelles that are surrrounded by a double membrane and contain own DNA; performs specific functions for the cell

stroma

The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water. contains ribosomes RNA and DNA

chromoplasts

type of plastid that stores pigments that are responsible for the bright colors in fruit and flowers

Amyloplasts

unpigmented plastids that store starch/grain in cell stems, tubers, seeds.

Acid hydrolases

Enzymes that degrade various macromolecules and
that require an acidic pH to function properly. Acid hydrolases are found within the lysosomes of cells., most lysosomal enzymes; active at pH 5 in lysosomes, but not int he cytoplasm which is about pH 7.2.

Catalase

The primary enzyme in peroxisomes; catalse catalyzes the hydrolysis of hydrogen peroxide (H2O2) into water and oxygen.

Lysosome

an organelle found in the cytoplasm of most cells (especially in leukocytes and liver and kidney cells) contains a single membrane. Used in cells as a means of storing hydrolyses. /synthesized on rough ER and transported to golgi complex then packaged int

Endosymbiont theory

the theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single organism. protoeukaryotes

Endoplasmic Reticulum

a system of membranes that is found in a cell's cytoplasm and that assists in the production, processing, and transport of proteins and in the production of lipids, An extensive membranous network in eukaryotic cells, continuous with the outer nuclear mem

Cisternae

enlarged areas of the sarcoplasmic reticulum on both sides of the transvers tubules, A space containing fluid, such as those occurring between the membranes of flattened sacs of the Golgi apparatus and the endoplasmic reticulum, also between the two membr

Lumen

The internal space enclosed by the ER membranes

smooth Endoplasmic reticulum

An endomembrane system where lipids are synthesized, calcium levels are regulated, and toxic substances are broken down., no ribosomes are found on surface; contains collection of enzymes that perform special tasks that include the synthesis of membrane l

Rough Endoplasmic Reticulum

A large system of folded membranes within a eukaryotic cell that has ribosomes bound to it, giving a rough appearnce. These ribosomes synthesize proteins that will ultimately be secreted from the cell, incorporated into the plasma membrane, or transported

Golgi complex

Plays an important role in the processing and packaging of secretory proteins and synthesizing complex polysaccharides. Vesicles that arise by budding off the ER are accepted here

Secretory Vesicles

contain secretions that will be discharged from the cell these vesicles will perform exocytosis (fusing with the plasma membrane to empty contents).

Peroxisome

resemble lysosomes in size but lack internal structure. Surrounded by a single membrane and found in plant and animal cells as well as in fungi, protozoa and algae. They perform functions that differ with cell type but all have the common property of both

glycosylation

addition of carbohydrate side chains to specific amino acid residues of proteins, usually beginning in the lumen of the endoplasmic reticulum and completed in the Golgi complex.

Vacuoles

Used for temporary storage or transport , Structure: Membrane surrounded "bags"; Small in animal cells; Large in plant cells.
Function: Storage of food, water, and other materials.

Ribosome

A cell organelle constructed in the nucleolus and functioning as the site of protein synthesis in the cytoplasm; Consists of rRNA and protein molecules, which make up two subunits.

large and small ribosomal subunits

Bacterial, mitochondria, chloroplasts are 70s
Euk 80S

Cytoplasm

consists of that portion of the interior of the cell not occupied by the nucleus. Includes mitochondria and also includes the cytosol

Cytosol

semifluid substance in which the organelles are suspend. in a animal cell can occupy more than half of the cells internal volume. Many cellular actives take place here including the synthesis of proteins, fats and initial steps in releasing energy from su

cytoskeleton

a microscopic network of actin filaments and microtubules in the cytoplasm of many living cells that gives the cell shape and coherence. plays an important role in cell movement and division

Microtubules

Largest element in cytoskeleton.

alpha tubulin

when tubulin forms, the GTP bound to this form remains intact and bound within the tubulin structure; it is at the minus end of the tubulin dimer, protein that joins with ?-tubulin to form a heterodimer that is the basic building block of microtubules.

beta tubulin

..., one of the monomeric globular proteins which associate to form the dimer, ?,?-tubulin, the basis of microfilaments.

Microfilaments

thinner, solid rods of protein that enable the cell to move or change shape when protein subunits slide past one another.

Intermediate filaments

range from 7-11nm in diameter, and strengthen the cell and help maintain its shape, stabilize the positions of organelles, and stabilize the position of the cell with respect to surrounding cells through specialized attachment to the cell membrane. Most s

turgor pressure

The pressure that is exerted on the inside of cell walls and that is caused by the movement of water into the cell

Svedberg units

Units of sedimentation coefficients of ribosome subunits (i.e. 30S and 50S) or intact ribosomes (i.e. 70S) when subjected to centrifugal force in an untracentrifuge.

axoneme

the internal structure of eukaryotic flagella and cilia consisting of microtubules, the motor protein dynein, and linking proteins

Cleavage furrow

the first sign of cytokinesis during cell division in an animal cell; a shallow groove in the cell surface near the old metaphase plate

gap junctions

specialized for the transfer of materials between the cytoplasm of adjacent cells. 2 types tight junction and adhesive junctions

G -actin

Globular acting molecule; polymerizes and forms a filamentous structures and is where Actin is synthesized.

F-actin

fibrous protein made of a long chain of G actin molecules twisted into a helix; main protein of the thin myofilament

intermediate filaments

Cytoskeletal filaments with a diameter in between that of the microtubule and the microfilament. Intermediate filaments are composed of many different proteins and tend to play structural roles in cells.Most stable, have tension bearing roles

tight junctions

membranes of neighboring cells are actually fused forming continuous belts around cell to prevent leakage of extracellular fluid

adhesive junctions

Linked adjacent cells but for the purpose of connecting them tightly into sturdy yet flexible sheets

bacteriophage

a virus that infects bacteria; used in some forms of recombinant DNA to transport foreign DNA into a host cell.

viroids

single stranded RNA molecules that have no surrounding capsids., A plant pathogen composed of molecules of naked circular RNA only several hundred nucleotides long.

Prions

infectious particle made up of protein rather than RNA or DNA, proteins that do not contain nucleic acid that cause proteins in the host cell to fold improperly and result in improper functioning

Limitation on Cell size

Smallest size is .2-.3 micrometer in diameter. Several factors limit cell size,The requirement for an adequate surface area/volume ratio, The rates at which molecules diffuse and the need to maintain adequate local concentrations of the specific substance

Surface area to Volume ratio

large cells have a lower ratio of surface volume to volume than smaller cells. As a cell increases in size its surface area does not keep pace with its volume and the necessary exchange of substances between the cell and its surrounding becomes more and m

Diffusion

movement in and out of cells. Which is a free unassisted movement of a substance from a gradient of high to low concentration. Molecular movement is limited by the dissuasion rates of molecules of various sizes and decreases as the size of the molecule in

Comparison of some properties of all cells

Microvilli

Tiny hair-like projections of the cytoplasmic membrane located only in the small intestine to facilitate absorption by increasing surface area.

binary fission

The type of cell division by which prokaryotes reproduce. Each dividing daughter cell receives a copy of the single parental chromosome.

hydrolases

Enzymes that carry out digestion by hydrolosis, uses H2O to breakdown polymers to monomers

leaf peroxisomes

in plant photosynthetic tissue, have a role in photorespiration, the light-dependent uptake of oxygen and release of carbon dioxide

lipid bilayer

double-layered sheet that gives cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings., Phospholipids, mostly, arranged in two layers; the structural basis of all cell membranes. Hydrophobic tails are sandwi

plasma membrane

thin outer boundary of a cell that regulates the traffic of chemicals between the cell and its surroundings

nucleoli

Dense masses of RNA and protein that manufacture ribosomes, several of these are located in the nucleus.

virus

particle made up of nucleic acid, protein, and in some cases lipids that can replicate only by infecting living cells.