Bio test 2

how were cells discovered through the invention of microscopy

thin sections of dried cork from plants were observed under a microscope

Who discovered the microscope

Robert Hooke

What is microscopic cell sizes measured in

micrometers

are eukaryotic or prokaryotic cells bigger

eukaryotic cells

Define Cell theory

all organisms are made up of cells

the cell is the fundamental unit of life

cells come from preexisting cells

2 types of prokaryotic cells

bacteria

archaea

4 kingdoms of eukaryotes

Protists

Fungi

Plants

Animals

Do pro or euk lack a membrance bound cell

pro

Are pro or euk larger

euk

Does pro or euk have chromosomes enclosed in a nucleus

euk

Does pro or euk cytoplasm have a larger number of distinch organelles

euk

Ribosomes

the site of protein synthesis

Nucleus

stores and transmits information

Mitocondria

Supply maximum ATP to cells

have 2 membranes

contain DNA

Chloroplasts

Sugar manufacturing centers in plants and algae

Have 2 membranes

contain DNA

Vacuoles

large, membrane bound structures found in plants and fungi

Storage centers (water and ions)

Peroxisomes

Oxidation of fatty acids, ethanol, or other compounds

Rough ER

Protein synthesis and processing

Smooth ER

Lipid synthesis and processing

Detoxification (liver)

Golgi apparatus

Protein, lipid, and carbohydrate processing (post office)

Lysocomes

Digestion and recycling

Cytoskeleton

Structural support

Movement of materials

Movement of whole cell (some species)

Endomembrane system functions

Manufactures, ships, recycles protein

Endomembrane system pathway

Proteins made in rough ER

Move to golgi apparatus for processing

Travel to correct destination for their function

What does the rough ER have that the smooth ER does not

Ribosomes

What is cisternae

a series of stacked, flat and membranous sacs (makes golgi apparatus)

Exocytosis

Material inside the cell packaged into vesicles and excreted into the extracellular medium

Endocytosis

Plasma membrane folds inward, to form a vesicle that brings substances into the cell

What cell are lysosomes only found in

animal cells

What is Tay-Sacs disease associated with

Lysosomal storage disease

What cell is cytoskeleton more prominent in

animal cells (looks stronger)

3 types of cytoskeleton

Actin filaments (microfilaments)

Intermediate filament

Microtubules

Microtubule structure

a hallow tube formed from tubulin dimers

Microfilament structure

a double helix of actin minomers

Intermediate filament structure

a strong fiber composed of intermediate filament proteins

Size order of the types of cytoskeleton (small to large)

microfilament

intermediate filament

microtubules

microfilament function (actin)

maintain cell shape by resisting tension (pull)

move cells via muscle contraction or cell crawling

divide animal cells in two

move organelles and cytoplasm in plants, fungi and animals

Intermediate filament genetic defect

epidermolysis bullosa

Intermediate filament function

maintain cell shape by resisting tension (pull)

anchor nucleus and some other organelles

Microtubules function

Maintain cell shape by resisting compression (push)

move cells via flagella or cilia

move chromosomes during cell division

assist formation of cell plate during plant cell division

provide tracks for intracellular transport

How do enzymes work

they lower the activation energy needed for the reaction to occur

1st step of enzyme catalysis

Initiation

Substrates are precisely oriented as they bind to active site

2nd step of enzyme catalysis

Transition state facilitation

interactions between substrate and active site R-groups lower activation energy

3rd step of enzyme catalysis

Termination

reaction products are released from enzyme

What is saturation kinetics in enzymes

Reaction rates level off because all available enzyme molecules are being used

Substrate specificity

key to enzyme action since only that enzyme works for that substrate

Example of specificity

lactose intolerance

How does temp affect enzymes

affects the folding anf movement of the enzyme and binding its substrates

How does pH affect enzymes

affects the enzyme’s shape and reactivity

Beyound optimal pH and temp what happnes to enzymes

denature and are non functional

What are enzyme inhibitors

a molecule that binds to an enzyme and decreases its activity

Competitive inhibitor

bind to the active site of the enzyme and prevent the substrate from binding

they compete with the substrate for the active site

Noncompetitive inhibitor / allosteric

bind to a site different from the active site

they slow down the reaction normally catalyzed by the enzyme by altering the enzyme shape

exmaple of a drug designed as an enzyme inhiibitor

penicillin

interfers with the synthesis of cell walls of reproducing bacteria

Cell communication

Cells must obtain information and respond to it

Cells must interact with other cells

2 examples of what cells communication through

Neurotransmitters

Hormones

Endocrine signaling

Signaling by means of molecules traveling through the bloodstream

Paracrine signaling

Involves two cells that are close to each other (ex. neurotransmitters)

Autocrine

the signlaing cell and the responding cell are one and the same (boomerang)

Juxacrine

direct contact between neighing cells (handshake)

Example of endocrine

Puberty

Hormones being released that were not before

Example of paracrine

Neurotramsitters

Example of autocrine

tumor cells

Example of juxtacrine

Killer cells

What does RTR stand for

Receptor activation

Transduction

Cellular Response

Reception

deliver message by binding to receptor molecules

only cells with appropriate signal receptors will respond

Ligand

signaling molecule

can be proteins, lipids, chemical molecules

Structure of ligands

small molecules (peptides, steroids, gases)

typically present in minute concentrations

have a large impact on the activity of target cells

Function of ligands

change shape and activity after binding to a hormone

Only cells with signal receptor will

Lipid soluble hormones

diffuse across the plasma membrane

receptors are in the target cells’ cytoplasm

nonpolar!!!!!!!!

Lipid insoluble hormones

large hormones do not cross the plasm membrane

receptors on cells surface extending out of the plasma membrane

one signal outside → more signals inside

polar!!!!!!

Transduction

Cell takes message and translates so nucleus can read it

Response

the message being sent

2 categories of response

A change in which genes are being expressed in the target cell

A change in the activation or deactivation of a particular target protein that already exists in the cell

Adrenaline rush (epinephrine)

fight or flight hormone

different effects throughout body

stimulates heart muscle to beat faster

Apoptosis

Programmed cell death

caused by signals that intentionally cause cell to die

cytoskeleton falls apart

Why would apoptosis happen

cell could be going rouge

virus

How do cells divide

Copy DNA

Separating DNA

Dividing the cytoplasm

Purpose of mitosis

to generate genetically identical cells

growth and replacement

asexual reproduction

Prokaryotic cell division

Binary fission

Eukaryotic cell division

mitosis

Why can bacteria take us down in days

Binary fission is a very short process (30 mins)

ex. sepsis

Process of binary fission

1. DNA is copied and protein filaments attach

2. DNA copies are separated and ring of protein forms

3. Ring of protein draws in membrane

4. Fission complete

Why should I care (binary fission)

Antibiotics (enzyme) interfere with bacterial division

Cell division cycle

G1-S-G2-M

Where is time mostly spent in the cell cycle

Interphase

What is the dividing phase

M phase

chromosomes are condensed into compact structures

What is the non dividing phase

Interphase

chromosomes are uncoiled

Cells are growing and preparing

What phase does DNA replication occur in

S phase

G0

Present in cell types that do not actively divide (ex. neurons)

G1

cell size increases

many regulatory proteins are made and activated

S

Synthesis

DNA is replicated

G2

Cell prepares for mitosis

Sister chromatids

Pair of replicates (copies of chromosomes)

How to identify sister chromotids

chromatids attached at the centromere

Ploidy

number of complete sets of chromosomes in a cell

ex. 46 in humans

Diploid

2n

46 chromosomes

sex chromosomes

Haploid

n

23 pairs

What happens during M phase

Mitosis (division or chromosomes)

Cytokinesis (division of cytoplasm)

Phases of M phase

Prophase

Prometaphase

Metaphase

Anaphase

telophase