Ch 6 lecture slides review

cell theory

cell theory

all cells come from cells

all cells have…

plasma membrane, DNA, ribosomes, and cytoplasm

prokaryote

contains its genetic material within a single chromosome

eukaryote

DNA exists in chromosomes, have membrane bound organelles

examples of eukaryotes

protists, fungi, animals and plants

example of prokaryotes

bacteria

why are cells so small?

high surface area to volume allows for things to enter and exit the cell faster

Light microscope (LM)

passes light through specimen, magnifies x1,000 its size, minimum resolution is 200 nm

Electron microscope (EM)

beams electrons onto specimen, magnifies x1,000,000 its size, minimum resolution is 0.2 nm

Scanning electron microscope (SEM)

beams electrons onto surface of specimen that is coated with thin film of gold → 3D image

Transmission electron microscope (TEM)

beam electrons through thin sections, specimen is stained with heavy metals

what’s the issue with using electron microscopes?

methods used to prepare specimen kills the cells

two domains of prokaryotic cells

bacteria and archaea

plasma membrane

consists of a lipid bilayer and proteins which make it a selective barrier

nucleus

location where the DNA is

nucleolus

region in nucleus active in synthesis of ribosomal RNA and ribosome assembly

nuclear envelope

double membrane that encloses the nucleus separating it from cytoplasm

nuclear lamina

Located on the nuclear side of the envelope and contains intermediate filaments that maintain the shape of the nucleus

Nuclear pore complex

Multi protein structure that forms channels through the nuclear envelope which allow proteins, RNA, and the export of ribosomes to move between the nucleus and cytoplasma

Chromatin

Complex of DNA and proteins (histones) that make up eukaryotic chromosome

Ribosome

Made of rRNA and ribosomal proteins that work with mRNA and catalyze synthesis of proteins

Endoplasmic reticulum (ER)

Network of membranous tubules and sacs that deal with lipid synthesis and membrane bound proteins along with secretory proteins are made

Smooth ER

Lack ribosomes, lipid synthesis, carbohydrate metabolism, detoxification, calcium storage

Rough ER

Studded with ribosomes, synthesis of membrane bound proteins and secretory proteins distributed by transport vesicles

Nucleoid

Region in prokaryotic cells where DNA is located not enclosed by a membrane

Golgi apparatus

Modifies proteins and lipids made in ER → sorts and package into transport vesicles, manufactures certain macromolecules

What happens to a transport vesicle when it arrives to the Golgi apparatus?

1. vesicles move from ER to golgi

2. vesicles come together to form new golgi cisternae

3. cisternal maturation: Golgi cisternae move in a cis-to-trans direction

4. vesicles form and leave Golgi, carrying specific products to other locations or to the plasma membrane for secretion

5. vesicles transport some proteins backward to less mature Golgi cisternae, where they function

6. vesicles also transport certain proteins back to ER, their site of function

What is the cis face of the goli?

The receiving side

What is the trans face of the goli

The shipping side

Lysosome

Membranous sac of hydrologic enzymes found in animal cells that hydrolyze (break) fats, polysaccharides, and nucleic acids and recycles organelles and macromolecules

Phagocytosis

Lysosome digesting food

Autophagy

Lysosome breaking down damaged organelles

What occurs in lysosomes to cause Tay-Sachs disease

Lysosomes lack functioning hydrolysis enzymes which causes them to be engorged with indigestible material → interferes with cellular activity

Food vacuoles

Contains food which is then digested by fusing with lysosome

Contractile vacuoles

Found in many freshwater protists in which pumps excess water out cell to maintain homeostasis

Central vacuoles

Found in plants and it hold organic compounds along with water

Endosymbiont theory

Early ancestors of eukaryotic cells engulfed and oxygen-using nonphotosynthetic prokaryotic cell. Evidence that supports this theory include:

1. mitochondria and chloroplasts are double membraned

2. both have circular DNA (like bacteria)

3. both grow and reproduce within the cell

Mitochondria

Smooth outer membrane and highly folded inner membrane, Produce atp

Intermembrane space

Region between in inner membrane and the outer membrane (of either mitochondria or chloroplast)

Mitochondrial matrix

Internal space enclosed by inner membrane

Cristae

Fold in the inner membrane of mitochondria

Chloroplast

Contain green pigment chlorophyll, functions in photosynthesis

Stroma

Internal fluid of chloroplast

Thylakoids

Disk shape membranous sac

Granum

Stack of thylakoids

Peroxisomes

Membrane bounded organelle that use molecular oxygen to oxidize organic molecules and makes H2O2

It does detoxification and break down fatty acids

Cytoskeleton

Network of fibers that help support the cell and maintain its shape (animal cells), allows for cell motility, provide monorails for vesicles to travel along, and regulate biochemical activities

3 main types of fibers that make up cytoskeleton listed from thickest to thinnest

Microtubules, intermediate filaments and micro filaments

Microtubules

Hollow rods that are made of tubulin. It shapes and supports cell, anchors organelles, serves as tracks, involved with separation of chromosomes

Microtubules is a a polymer of

Tubulin subunits which is a heterodimer of alpha-tubulin and beta-tubulin, grow and shrink by adding and removing them

Kinesins

Motor molecules that move vesicles along microtubule tracks, ATP is hydrolyzied to ADP allowing forward movement

Flagella

Undulating motion like tail of fish

Cilia

Alternating power and recovery stroke like oars pf racing crew boat

Dynein

Motor protein that when phosphorylated by ATP it causes it to have a conformational change

Dynein structure

“9+2”, 9 microtubule doublets line in a circle while there are 2 center microtubules

How does dynein allow movement

in order to move right it pushes the left microtubule up and since they are connected by nexin proteins it bends to the right rather than go up

Microfilaments

Solid rods built as twisted double chain, formed by actin subunits. They beat tension and resist pulling forces

What does ATP hydrolysis do to the stability of actin polymer

Decreases stability

Sliding model theory

Actin filaments and filaments consisting of myosin arranged parallel slides towards each other

Cytoplasmic streaming

Circular flow of cytoplasm, speeds distribution of materials

Intermediate filaments

Support cell shape and fix organelles

Cell wall

In plant cell maintains shape and prevents excessive uptake of water

Plasmodesmata

Channels between adjacent plant cells

Extracellular matrix (ECM)

Protection, support adhesion, movement, regulation

Glycoproteins

40% of proteins in body, major protein in bone, tendon and skin

Proteoglycan

Hold a lot of water + flexible shock absorbers, small protein linked to several carbohydrates

Tight junctions

Pressed together, prevent leakage of fluid

Desmosomes

(Anchoring junctions) Fasten cells together into strong sheets→ like skin

Gap junctions

(Communicating junctions) provide cytoplasmic channels between adjacent cells → smooth muscle