Apbio Unit 2

Cell wall

Structure: Rigid, tough, made of cellulose
Function: protects and supports the cell outside of the plasma membrane in plant cells

Plasma membrane

Structure: 2 phospholipids, with cholesterol to keep semi-fluidity, integral/transport protein, peripheral proteins, glycoproteins and carbohydrate on the outside
Function: protects the cell, performs active transport and passive transport, moves materials in and out of the cell, communication

Cytoplasm

Structure: cytoplasm is semi-fluid with cytoskeleton as mesh network of fibers
Function: support, motility, and regulation of the cell

Nucleus

Structure: contains Nucleolus and chromosomes
Function: control center for cell activities, contains DNA, makes chromosomes

Nuclear envelope

Structure: thin covering made of internal membrane
Function: cover and protect nucleus

Nucleolus

Structure: small dark spot in nucleus
Function: produce ribosomes

Endoplasmic recticulum

Structure: clear, tubular system of tunnels made of internal membrane (called cisternae)
Function: transport material around cell

Ribosomes

Structure: small specks of RNA in cytoplasm or on ER
Function: make proteins

Mitochondria

Structure: bean shaped, double membrane, (inner membrane=folded=cristae), matrix=space in middle
Function: powerhouse of cell, site of cell respiration (supplies ATP for cell through cell resp using Oxygen and glucose)

Central Vacuole

Structure: membranous sac
Function: stores water and organic materials in plants

Chloroplast

Structure: green structures containing chlorophyll, outer membrane, inner membranes in shape of sacs (thylakoids), stack of thylakoids= granum, stroma=fluid part outside of grana Function: capture sunlight and use it to make food through photosynthesis

Lysosome

Structure: small, round structures containing digestive enzymes
Function: digest older cell parts, food, other object

Smooth ER

Structure: clear, tubular system of tunnels made of internal membrane, no ribosomes
Function: lipid synthesis, carbohydrate synthesis, detoxification

Rough ER

Structure: clear, tubular system of tunnels made of internal membrane, with ribosomes
Function: help make proteins and transport them to the golgi, membrane production

Chromosomes

Structure: 2 chromatids help together by centromere, holds genes
Function: hold DNA during cell replication

Golgi apparatus

Structure: cis face (receives from ER), trans face (produces vesicles that pinch off and travel)
Function: finalizes, packages, and

Vesicles

Structure: membranous sac
Function: either store water or get ride of excess water (vacuoles=large version of these)

Stroma

Fluid area outside the grana

Cytoskeleton

Mesh network of fibers inside cytosol to support and regulate stuff in the cell. Made of 3 types of fibers (microtubules--hollow, microfilaments--solid-helps with movement, intermediate filaments--fix position of organelles)

Diffusion

Movement of molecules from high to low concentration. Either active or passive

Osmosis

Diffusion of water across selectively permeable membrane

Hypertonic

Refers to the solution with a greater solute concentration (more solute outside cell), less water, water leaves the cell=shriveled

Hypotonic

Refers to the solution with lesser solute (more solute inside cell), more water, water floods the cell=bursts/turgor pressure

Isotonic

When solutions are at equilibrium

Passive transport

Molecular movement with the concentration gradient, requires no energy, 2 types are facilitated diffusion and simple diffusion through pores

Active transport

Molecular movement against concentration gradient, energy required, allows cell to maintain specific internal concentration regardless of environment

Facilitated diffusion

Passive transport that uses integral proteins to help transport the materials (still no use of energy)

Sodium potassium pump/electrogenic pumps

Main kind of active transport in animals. Look at diagram in PowerPoint!!!

Exocytosis

Transport out of a cell

Endocytosis

Transport into a cell

Phagocytosis

Cell eating

Pinocytosis

Cell drinking

Receptor mediated Endocytosis

Takes cholesterol out of the blood

Water potential

Tendency for water molecules to diffusion, moves from high water potential to low water potential

Crenate

Animal cells shrinking

Plasmolysis

Plant cell shrinking

Lysing

Animal cell bursting because of too much water

Tutor pressure

Plant cells when there is lots of water in the cell

Water potential=solute potential + pressure potential

Water potential equation

Solute potential

More solute=more negative number=lower water potential

Pressure potential

0 in animal cell, second component of water potential equation

megapascal: MPa

What is water potential measured in?

Symbiosis

2 creatures living together in which both organisms benefit from the relationship

Signal transduction pathways

Process by which a signal on a cell's surface is converted to a specific cellular response in a series of steps

Sutherland

person who came up with the signal transduction pathways and determined that the cell membrane plays a huge role in cell communication

Reception, transduction, response

Three stages of signaling

Reception

Detection of the first message in the sing tans path...usually receptor is an integral protein (the integral protein changing shape when the signaling molecule touches it=start of pathway), signal molecules bind to recept proteins that recognize the specific signal.

Ligand

Term for a small molecule that specifically binds to a larger one. Ligand binding causes a receptor protein to undergo a shape change=starts whole signal transduction pathway

G-protein linked, tyrosine-kinase, ion channels

3 types of reception

G protein linked

Most common form of reception--?!?!

Tyrosine-kinase

Receptors located on membrane, catalyze the transfer of P from ATP to tyrosine which in turn causes polypeptide to aggregate and phosphorylation of receptor which activates relay proteins...causes a single ligand-binding event to trigger many pathways....can also cause worst form of Brest cancer

Ion gated channels

Gated channels that open only for certain specific ions. one example is the sodium potassium pump

Transduction

Relays message in the signal transduction pathway, usually proteins, uses protein phosphorylation and sometimes second messengers, use cascade or immediate response or ion gated channel

Second messenger

The ligand in between the G protein the cell response, this protein is made to relay the message to the protein that is going to respond

Response

Activation of a certain gene, stimulation of glycogen breakdown by epinephrine, regulation: examples: aptosis, transcription of protein, growing (cell division, end game of all communication

No distance, short distance, long distance/large audience

3 ways for a cell to communicate with another cell

Cell to cell contact

No distance communication involves __________ (in relation to distance between cells). (Uses cell [gap] junctions and cell-cell recognition)

Plasmodesmata

Plant cell junction used for cell to cell communication

Local regulator between cells

Short distance communication involves _______ (in relation to distance between cells)

sending the message to multiple cells

Long distance/large audience communication involves ___________ (in relation to distance between cells)

Immune response

Example of no distance communication in which an antigen goes into an APC cell which activates the T helper so this cell know the shape of the bad cell=contact with APC cell=cell communication to kill antigen

Endorphins

Example of short distance communication in which a message is sent through one neuron and then to another through the release of endorphins bc the neurons are not actually touching

Growth hormone

Example of long distance/large audience communication in which lots of growth hormones are released and everything that receives the message in the hormone starts to grow (except brain)

Paracrine signaling, synaptic signaling

Two kinds of local signaling

Paracrine signaling

Transmitting cell secretes molecules to influence neighbors

Synaptic signaling

One cell produces a neurotransmitter (chemical signal) that crosses the synapses (space bt nerve cells)

Endocrine signaling

Long-distance signaling example in which cells release chemicals into the blood, those chemicals travel to target cells

Protein kinase

Enzyme that transfers phosphate from ATP to a protein

Protein phosphatase

Enzyme that can rapidly remove phosphate groups from proteins (aka dephosphorylation)