lysosome

spherical, membraneous organelles which contain activated digestive enzymes. If these enzymes are released into the cytoplasm, they cause the cell to self-digest

G₁

first subphase of interphase characterized by vigorous growth and metabolism

Telophase

Final phase of mitosis.

Cell Theory

1) A cell is the basic structural and functional unit of living organisms.

2) Activity of an organism depends on both the individual and collective activities of its cells.

3) Biochemical activities of cells are dictated by their shapes and forms.

4) Continuity of life from one generation to another has a cellular basis.

Cytoplasm

intracellular fluid containing organelles

Metaphase

Second phase of mitosis or meiosis in which the duplicated chromosomes line up along the equatorial plate of the spindle.

Anaphase

the third stage in mitosis or meiosis following metaphase in which the daughter chromosomes move away from each other to opposite ends of the cell.

Prophase

first stage of mitosis or meiosis in eukaryotic cell division, during which the nuclear envelope breaks down and strands of chromatin form into chromosome

In RNA transcription, what replaces thymine in DNA, to make it slightly different?

Uracil

Passive forms of diffusion

Osmosis and simple diffusion

carrier assisted diffusion

a type of facilitated diffusion that involves the binding of a substrate to a carrier causing a change in the carrier. Carriers can change shape and assist big molecules through the cell wall.

mitochondria

principle site of ATP synthesis aka the "powerhouse of the cell"; contain DNA, RNA and ribosomes

ribosomes

site of protein synthesis

Golgi Apparatus

Cell organelle that acts as a packaging warehouse for protein.

desmosome

A membrane junction that acts as a spot weld anchoring cells together.

types of proteins found in a plasma membrane

1) Integral, 2) Peripheral

types of junctions found in plasma membrane

1) gap junctions

2) desmosomes

3) tight junctions

aquaporin

Transmembrane proteins that form specific channels, or PORES, in a cell membrane that allow only water to move freely in single file diffusion through the wall.

Forms of Passive Transport

1) Osmosis

2) Simple Diffusion

3) Carrier facilitated transport

4) Channel mediated transport

Diffusion

Tendency of molecules or ions to move from an area where they are in higher concentration to an area where they are in lower concentration.

Active Cell Process

Cell requires ATP (metabolic energy) to move substances across the cell membrane

osmotic pressure

The tendency of water to move into the cell by osmosis.

hydrostatic pressure

Back pressure exerted by water against the membrane.

hypotonic solution

contain a lower concentration of nonpenetrating solutes

cell

structural unit of all living things

gap junction

a communicating junction between adjacent cells; present in electrically excitable tissues such as the heart and smooth muscle

cadherins

thin linker protein filaments that extend from plaques and fit together like teeth of a zipper in the intercellular space

tight junction

type of membrane junction that is a series of integral protein molecules in the plasma membranes of adjacent cells fuse together, forming an impermeable junction that encircles the cell

membrane protein functions

1) Transport

2) Receptors for signal transduction

3) Attachment to cytoskeleton and extracellular matrix

4) Enzymatic Activity

5) Intercellular joining

6) Cell-cell communication

glycocalyx

fuzzy, sticky carb rich area at cell surface; sugar covered proteins

lipid rafts

20% of cell membrane surface; concentrating platforms for certain receptor molecules; dynamic assemblies of saturated phospholipids associated with unique lipids sphingolipids and lots of cholesterol.

peripheral proteins

cell membrane proteins that are NOT embedded in the lipid bilayer; include a network of filaments

integral proteins

cell membrane proteins that are firmly inserted into the lipid bilayer; most are transmembrane

plasma membrane/cell membrane proteins

make up the cytoskeleton and 50% of the cell membrane mass

cholesterol

20% of cell membrane lipids; has polar head and nonpolar tail; stabilizes the membrane

glycolipids

lipids with attached sugar groups that comprise 5% of the plasma membrane

hydrophilic

likes water

phospholipids

lollipop shaped molecule with a polar head that is charged and hydrophilic; has a non polar tail made of 2 fatty acid chains that are hydrophobic

membrane lipids

form fabric of the plasma membrane

membrane lipids

1) phospholipids, 2) glycolipids, 3) cholesterol, 4) lipid rafts

hydrophobic

doesn't like water

organelles

small cell structures that perform specific cell functions

mitosis

cell division

Cell functions that involve protein coated vesicles

endocytosis and transcytoisis

centrioles

a small, cylindrical cell organelle, seen near the nucleus in the cytoplasm of most eukaryotic cells, that divides in perpendicular fashion during mitosis, the new pair of centrioles moving ahead of the spindle to opposite poles of the cell as the cell divide

peroxisome

a cell organelle containing catalase, peroxidase, and other oxidative enzymes and performing essential metabolic functions, as the decomposition of fatty acids and hydrogen peroxide

types of vesicular transport

exocytosis, endocytosis, transcytosis, and substance trafficking

simple diffusion

Gases and Fats do this within a cell; when non-polar lipid soluble substances disperse directly through the phospholipid layer, requiring NO ATP (cell energy)

passive cell processes

simple diffusion, carrier mediated facilitated diffusion, channel mediated facilitated diffusion, osmosis

cytoskeleton

comprised of microtubules, microfilaments and intermediate filaments

Rough E.R.

outside is studded with ribosomes; area of protein synthesis within the cell

nucleus

control center of the cell

channel mediated diffusion

Facilitated diffusion that involves channels that do not change shape. Good for water.

types of channel mediated diffusion

leaky and gated

tonicity

the ability of a solution to make a cell shrink or swell

isotonic

when a solution has the same solute concentration as that of the cytosol

Secondary Active Transport

a hitchhiking type of cellular transport that depends on an ion gradient created by a primary active transport; requires ATP but only for the primary active transport

hypertonic

a solution has a greater solute concentration than that of the cytosol; cells lose water by osmosis and shrink (crenation)

endomembrane system

a system of organelles that work together maintly to produce, degrade, store, and export biological molecules, and degrade potentially harmful substances.

microfilaments

thinnest elements of the cytoskeleton that are semiflexible strands of protein actin

functions of lysosomes

break down bone to release calcium ions into the blood, digest particles taken in by endocytosis (bacteria, viruses and toxins), degrade worn out organelles, perform metabolic functions such as glycogen break down and release, break down useless tissues (webs between fetal digits and uterine lining during menstruation)

centrosome

microtubule organizing center with a 9x3 array.

microvilli

fingerlike extensions of the plasma membrane that project from an exposed cell surface

found on the surface of absorptive cells such as intestinal and kidney tubule cells

microvilli

interphase

period from cell formation to cell division; not a part of cell division or replication

subphases of interphase

G1, S, G2

function of mRNA

carries transcript information

CAM

cellular adhesion molecule that provides temporary binding sites that guide cell migration and other cell-cell interactions

tight junctions

prevent fluids and most molecules from moving between cells

In what tissue are desmosomes found?

skeletal muscle, ligaments and tendons

In what tissue are tight junctions found?

integumentary system

In what tissue are gap junctions found?

heart muscle, nervous tissue, and some smooth digestive muscle

types of membrane transport

passive and active

passive membrane transport

does not require ATP

Fats and gases diffuse this way

simple diffusion

What determines whether or not a substance can passively permeate a membrane?

lipid solubility of the substance, channels of appropriate size, and carrier proteins

facilitated diffusion

transmembrane integral proteins transport specific polar molecules (e.g., sugars and amino acids)

carrier proteins

transport certain lipophobic molecules (glucose, ions or amino acids)

types of facilitated diffusion

channels and carrier proteins

types of facilitated diffusion using channel proteins

leakage and gated

Leakage channels are always_____________.

open

Gated channels are controlled by___________ and _____________.

chemical, electric signals

Aquaporins transport other things other than water.

False.

Required by active transport

carrier proteins (solute pumps)

active transport

moves solutes against a concentration gradient

secondary active transport

depends on an ion gradient created by primary active transport

endocytosis

often receptor mediated, therefore very selective

phagocytosis

pseudopods engulf solids and bring them into the cell's interior

pinocytosis

cell drinking

Macrophages and some white blood cells participate in _________________.

phagocytosis

Occurs in nutrient absorption in the small intestine.

pinocytosis

receptor mediated endocytosis

clathrin coated pits provide main route for endocytosis and transcytosis

uptake of enzymes, low density lipoproteins, iron and insulin

occur with receptor mediated endocytosis

Roles of cell adhesion molecules

anchor cells to extracellular matrix or to each other, assist in movement of cells past one another, CAMs of blood vessel lining attract white blood cells to injured or infected areas, stimulate synthesis or degradation of adhesive membrane junctions, transmit intracellular signals to direct cell migration, proliferation, and specialization.

cell to environment interactions

involves glycoproteins and proteins of the glycocalyx

Roles of membrane receptors

contact signaling (touching and recognition of cells), chemical signaling (interaction between receptors and ligands), G protein linked receptors (ligand binding activates a G protein, affecting an ion channel or enzyme or causing the release of an internal second messenger

comprised of cytosol, cytoplasmic organelles and inclusions

cytoplasm

components of cytosol

water with solutes such as protein, salts, sugars, etc.

cell inclusions

granules of glycogen or pigments (melanin), lipid droplets, vacuoles, and crystals

nonmebranous organelles

cytoskeleton, centrioles, and ribosomes

membranous organelles

mitochondria, peroxisomes, lysosomes, endoplasmic reticulum, Golgi apparatus

ER

interconnected tubes and parallel membranes enclosing cisternae, continuous with nuclear membrane/envelope

rough ER

studded with ribosomes, manufactures all secreted proteins, synthesizes membrane integral proteins and phospholipids

smooth ER

tubules arranged in a looping network, enzyme functions

synthesis of steroid based hormones

smooth ER

In skeletal and cardiac muscle cells, smooth ER...

storage and release of calcium

In liver cells, smooth ER...

metabolizes lipids and cholesterol, breakdown of glycogen

In kidney cells, smooth ER...

detoxifies drugs, pesticides and carcinogens

In intestinal cells, smooth ER...

absorbs, synthesizes, and transports fats

modifies, concentrates, and packages proteins and lipids

Golgi Apparatus

autolysis

destruction of cells

free radicals

highly reactive chemicals with unpaired electrons

involved in cell motility, change in shape, endocytosis and exocytosis

microfilaments

intermediate filaments

tough, insoluble ropelike protein fibers

resists pulilng forces on the cell and attaches to desmosomes

intermediate filaments

microtubules

dynamic hollow tubes, most of which radiate from centrosome

determine the overall shape of cell and distribution of organelles

microtubules

chromatin

threadlike strands of DNA that are arranged in fundamental units called nuleosomes

motor molecules

ATP powered protein complexes that function in motility

cell center near the nucleus organizes the mitotic spindle

centrosome

Red blood cells are a) anucleate or b) uninucleate?

anucleate

Most cells are a) anucleate or b) uninucleate?

uninucleate

cells with more than one nucleus (multinucleate)

skeletal muscles cells, bone destruction cells, and certain liver cells

a double membrane barrier containing pores that maintains the shape of the nucleus

nuclear envelope/nuclear membrane

nucleoli

involved in rRNA synthesis and ribosome subunit assembly

nuclear pores

regulate transport of large molecules into and out of nucleus

cell division

mitosis

G₀

gap phase in cells that permanently stop dividing

S

second subphase of interphase that is DNA replication

G₂

third subphase of interphase that is characterized by the preparation for division

types of G₀ cells

nerve, cartilage, heart

90% of a cell's life is spent in this phase

interphase

DNA replication

DNA helices begin unwinding from the nucleosomes, helicase untwists the double helix and exposes the complementary chains, the Y shaped site of replication is the replication fork, each nucleotide strand serves as a template for building a new complementary strand

Does DNA polymerase work in one direction or two directions during DNA replication?

one direction

ligase

splices together short segments of a discontinuous DNA strand during replication

Four phases of mitosis in order

prophase, metaphase, anaphase, and telophase

essential for growth and repair of cells

mitosis (cell division)

cytokinesis

division of cytoplasm by cleavage furrow

semiconservative replication

2 DNA molecules formed from the original strand

Lagging strand works toward or away from the fork in helicase?

away

helicase

unwinds the double helix and exposes bases of DNA

amino acids the comprise DNA

adenine, cytosine, thymine, guanine

prophase

chromosomes become visible, each with two chromatids joined at a centromere

mitotic spindles and asters form

prophase

centrosomes spearate and migrate toward opposite poles

prophase

second phase of mitosis

metaphase

centromeres of chromosomes align at the equator

metaphase

metaphase plate

plane midway between the poles

shortest phase of mitosis

anaphase

anaphase

when centromeres of chromosomes split simultaneously, and each chromatid now becomes a chromosome

"Go signals" of cell division

critical volume of cell when area of membrane is inadequate for exchange, 2) chemicals

Cdks (cylin-dependent kinases)

a go signal for control of cell division

Cytokinesis begins at which phase of mitosis?

anaphase

A ring of actin microfilaments contract to form a cleavage furrow on a cell, pinching apart two daughter cells.

cytokinesis

The phase during which chromosomes stop moving

telophase

During telophase these reappear and these disappear.

nucleoli, spindles

three main types of RNA

mRNA, rRNA, and tRNA

What is the master blueprint for protein synthesis?

DNA

gene

segment of DNA with blueprint for one polypeptide (protein)

triplets of nucleotide bases form

a genetic library

Specifies coding for an amino acid

triplet

mRNA

messenger RNA

rRNA

ribosomal RNA

tRNA

transfer RNA

carries instructions for building a polypeptide, from gene in DNA to ribosomes in cytoplasm

mRNA

structural component of ribosomes that, along with tRNA, helps translate message from mRNA

rRNA

binds to amino acids and pairs with bases of codons of mRNA at ribosome to begin process of protein synthesis

tRNA

only type of RNA in nucleus

mRNA

site of both tRNA and mRNA

ribosomes

Steps of protein synthesis

transcription and translation

transcription

transfers DNA gene base sequence to a complementary base sequence of an mRNA (it transcribes)

RNA polymerase

an enzyme that oversees synthesis of mRNA andunwinds the DNA template

transcription factor

loosens histones from DNA in area to be transcribed, binds to promoter, mediates the binding of RNA polymerase to promoter

promoter

a DNA sequence specifying start site of gene to be transcribed in transcription

transcription

making a partial copy of DNA

replication

making an entire copy of DNA

translation

converts base sequence of nucleic acids into the amino acid sequence of proteins

codon

a complementary three base sequence on mRNA

translation involves what types of RNA?

all of them

translation

anticodon of a tRNA binds to its complementary codon and adds its amino acid to the forming protein chain

intron regions of DNA code

junk

signal recognition particle SRP

found in rough ER; binds with mRNA-ribosome complex during protein synthesis

ubiquitin

it tags damaged or unneeded soluble proteins in cytosol

antisense RNA

prevents protein coding RNA from being translated

microRNA

small RNAs that interfere with mRNAs made by certain exons

riboswitches

folded RNAs that act as switches regulating protein synthesis in response to environmental conditions

all cells of the body contain the same DNA but are not_______________.

identical

cell differentiation

development of specific and distinctive features in cells

rapid cell death

apoptosis

____________ ___________ in the embryo channel cells into specific delopmental pathways by turning some genes off.

chemical signals

wear and tear theory of cells

little chemical insults and free radicals have cumulative effects

genetic theory

cessation of mitosis and cell again are programmed into genes.

may determine the number of times a cell can divide

telomeres

telomeres

strings of nucleotides on the ends of chromosomes