Lecture 6-Cellular Structure of Eukaryotic cell

1) Cells can’t depend on diffusion to supply interior of cell with nutrients

2) External cell membrane would be insufficient to house enough bioenergetic complexes

Problems of large cell size(2)

1.) Endomembranes increase membrane surface area w/o increasing cell volume

2.) Enclosed certain metabolic activities increase [enzyme] and [substrates] allowing rxns to go faster

3.)Allows for different environments within cells. Ex: low acidic pH in lysozymes

4.) protects cytoplasm from harmful compounds. (Ex: lysosomes-hydrolytic enzymes and peroxisomes-peroxide)

4 Advantages of organelles

cellulose(algae) and chitin(fungi)(no peptidoglycan)

Eukaryotic cell wall composed of *blank and *blank

Not sensitive to chloramphenicol and streptomycin(unlike prokayotes)

How do Eukaryotic ribosome react to chloramphenicol and streptomycin

Actin, Tubulin, etc

Cytoskeletal proteins of eukarya

Composed of a(alpha) and B(beta) tubulin

What are eukaryotic cells flagella composed of?

• Microtubules, tubulin

• Nine pairs + two arrangements

Structure of eukaryotic flagella and cilia

Plants, algae, fungi

What eukaryotic groups have cell walls?

• Carbohydrates: cellulose, chitin, glucan, mannan.

• No peptidoglycan, antibiotic such as penicillin and cephalosporin do not affect eukaryotic cells.

What are the main carbohydrate and peptidoglycan components of eukaryotic cell walls?

penicillin and cephalosporin

What two antibiotics have no effect of eukaryotic cell walls due to their lack of peptidoglycan?

Sterols

unique to eukaryotic plasma membranes

• Proteins.

– Peripheral proteins.

– Integral proteins.

– Transmembrane proteins

Three types of Proteins in Eukaryotic Plasma Membranes

Phagocytosis

_____________: Pseudopods extend and engulf particles.

Pinocytosis

____________: Membrane folds inward bringing in fluid and dissolved substances

-Allows ingestion and export of things that are too large to be accomodated by a channel or pore

Why is endocytosis and exocytosis important?

membrane-spanning protein complexes

Bacteria do not perform endocytosis or exocytosis*. They import and export material through __________________________

endocytosis

Viruses that attack eukaryotic cells exploit ___________ to gain entry to

the cell.

pathogens and symbionts

In a few cases, bacteria are endocytosed by eukaryotic cells, but

instead of being digested, evade the lysosome and live within the host

cell. Two examples of this are

Cytoplasm

Substance inside plasma and outside nucleus

Cytosol

Fluid (soluble) portion of cytoplasm

Microfilaments, intermediate filaments, microtubules

3 main components of the cytoskelton in Eukaryotes

Cytoplasmic streaming

Movement of cytoplasm throughout cells

Nucleus

Organelle that contains chromosomes

ER

Organelles that are in the Transport network

Golgi Complex

Membrane formation and secretion organelle

Lysosome

Organelle that works as digestive enzymes

Vacuole

Brings food into cells and provides support

Mitochondrion

Cellular respiration

Chloroplast

Photosynthesis organelle

Peroxisome

Oxidation of fatty acids; destroys H2O2

Ribosome and Centrosome

2 Eukaryotic non-membrane bound organelles

Centrosome

Consists of protein fibers and centrioles, plays important roles in cell division.

 Nuclear membrane (double membrane)

 Nuclear pore, transport control

 Nucleolus, ribosome RNA synthesis

 Repository of genetic information (chromatin, DNA bound by histones)

List 4 bullet points about the Nucleus

70S

Ribosomal components of chloroplasts and mitochondria

 Extensive network of membranous sacs or tubules

 Rough ER, ribosome

 Smooth ER, no ribosome attached

 Protein and lipid synthesis

 Transport of material

List 5 bullet points of the Endoplasmic Reticulum

 Membranous organelle made of cisternae stacked on each other

 Involved in modification, packaging, and secretion of materials for various purposes

List 2 bullet points of the Golgi Complex

• Membrane-bound vesicles found in most eukaryotes

• Involved in intracellular digestion

• Contain hydrolases, enzymes which hydrolyze molecules and function best under slightly

acidic conditions

• Maintain an acidic environment by pumping protons into their interior

List 4 bullet points of the Lysosomes

Yoshinori Ohsumi

Who discovered autophagy(self-eating) in 2016 and Received a Nobel Prize

-Double Membraned

-Inner membrane is folded as cristae

-Many enzymes that involve cellular respiration are on cristae

-DNA(genome)

-70S ribosome

-Energy production

List the 6 bullets that describe the Mitochondria

-Site of TCA cycle

-Site where ATP is generated by electron transport and oxidative phosphorylation

-About the same size as bacterial cells

-Reproduce by binary fission as do bacterial cells

-Critical roles in the regulation of cell death and innate immune system

6 more bullet points about the Mitochondria

-contains porins similar to the outer membrane of Gram-negative bacteria

Outer membrane structure of mitochondria

-highly folded to form cristae(s. crista

-location of enzymes and electron carriers for electron transport and oxidative phosphorylation

Inner membrane of mitochondria

-ribosomes(same size as bacteria)

-mitochondrial DNA(may be circular like bacteria)

-enzymes involved in TCA and enzymes for catabolism of fatty acids

What 3 things are in the matrix enclosed by inner membrane?

-Site of photosynthetic reactions

• Pigment-containing organelles observed in plants and algae

• Surrounded by double membrane

• 70S, DNA genome, binary fission

List 4 bullet points about Chloroplast

Endosymbiotic Theory

The theory that:

-Mitochondria were bacteria

-Chloroplasts were cyanobacteria

-Infected or engulfed by other species

-Ended up living together

Mitochondria and Chloroplasts contain:

-same size, shape and binary fission of bacteria

-Circular DNA genome

-70S ribosome

list all evidence for the endosymbiotic theory

Lynn Margulis

scientist who discovered Endosymbiotic Theory

cyanobacterial

Chloroplasts contain DNA similar to ______________ DNA, leading scientists to believe that they were ingested by eukaryotic cells

proteobacterium (or the proteobacterium attempted to infect it)

Early in cellular evolution, a larger cell ingested a

________________. This developed into the mitochondria

-Different membranes

-Archaeal ribosomes similar to eukaryotic ribosomes

-Many archaea live in harsh environments

-Separate domain

List all the reasons why Archaea are different from bacteria

-Archaea

-Bacteria

-Mitochondria and Chloroplasts of Eukaryotes

What organisms have 16s rRNA gene sequence?

D. peptidoglycan

The plasma membrane of eukaryotes contains all of the following except

A. phosphoglycerides.

B. sphingolipids.

C. sterols.

D. peptidoglycan

E. All of the choices

Which of the following is a function of the

mitochondrion?

A. Tricarboxylic acid cycle enzyme

reactions.

B. Electron transport.

C. ATP synthesis.

D. Regulation of cell death and innate

immune responses

E. All of the choices

c. 30S + 50S

Prokaryotic ribosomes are composed of two

subunits of what sizes?

a. 20S + 50S

b. 30S + 40S

c. 30S + 50S

d. 40S + 60S