Q.Q. 8/27/18How did people get sick in the

15th century?

The “A” TEAMCH. 1 & 25 Quiz

Great work!

▶ Mia Crossen▶ Belen Hernandez▶ Karla Herrera▶ Emily Lindley▶ Guilherme

Machado

Chap. 6- The Cell

Cellular Organization

• Cell• Tissue – group of cells functioning

together.• Organ – group of tissues

functioning together.• Organ System – group of organs

functioning together.• Organism – group of organ

systems functioning together.

The Cell

• Cell = The simplest collection of matter that can live independently (contains all the qualities of life and can perform on its own)

Redi and Spontaneous Generation

Spontaneous generation: the idea that living organisms generate from nonliving matter, as inferred from rotting meat giving rise to maggots (fly larvae)

Animation of Redi’s experiment

The History of the Cell

• The Cell–The basic unit of an organism–Discovery made possible by

the invention of the microscope

Scientists Animation

Microscopes and Cells– Robert Hooke used the first

compound microscope to view thinly sliced cork cells.

– Hooke was the first to use the term “cell”.

Microscopes and Cells

1600’s:–Anton van

Leeuwenhoek first described living cells as seen through a simple microscope.

Microscopes and Cells1830’s:

–Mathias Schleiden identified the first plant cells and concluded that all plants

made of cells.- Thomas Schwann made the same conclusion about animal cells.

Cell Theory:1. All organisms are made up of one or

more cells. (Schleiden, Schwann, Hooke)

2. The cell is the basic unit of all organisms. (Hooke, Leeuwenhoek)

3. All cells come from other pre-existing cells. (Virchow)

The Cell• Tools to study the cell

- Microscopy: used for cells too small to see with the naked eye

-Light Microscope *we use

- Electron Microscopes:

*Scanning

* Transmission

Figure 6.2 10 m

1 m

0.1 m

1 cm

1 mm

100 μm

10 μm

1 μm

100 nm

10 nm

1 nm

0.1 nm

Atoms

Small molecules

LipidsProteins

Ribosomes

VirusesSmallest bacteria

MitochondrionMost bacteriaNucleus

Most plant andanimal cells

Human egg

Frog egg

Chicken egg

Length of somenerve andmuscle cells

Human height

Una

ided

eye

Ligh

t mic

rosc

opy

Elec

tron

mic

rosc

opy

Super-resolution

microscopy

Three important parameters of microscopya. Magnification, the ratio of an object’s image

size to its real sizeb. Resolution, the measure of the clarity of the

image, or the minimum distance of two distinguishable points

c. Contrast, visible differences in parts of the sample

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Brightfield(unstained specimen)

Brightfield(stained

specimen)

50 μ

m

Confocal

Differential-interference-contrast (Nomarski)

Fluorescence

10 μm

Deconvolution

Super-resolution

Scanning electronmicroscopy (SEM)

Transmission electronmicroscopy (TEM)

Cross sectionof cilium

Longitudinal sectionof cilium

Cilia

Electron Microscopy (EM)

1 μm

10 μ

m50

μm

2 μm

2 μm

Light Microscopy (LM)

Phase-contrast

Figure 6.3

The Cell

• Tools to study the cell- Microscopy

- Light Microscope (what we use the most)- Light is passed through the specimen- Magnification- ratio of image to actual

size (usually a 1000x max)- Resolution- Clarity of image- Can usually resolve objects down to

.2um or 200 nm (about the size of bacteria)

• Light microscope (LM)

• visible light is passed through a specimen and then through glass lenses, which refract (bend) the light, so that the image is magnified

• can magnify effectively to about 1,000 times the size of the actual specimen

• Various techniques enhance contrast and enable cell components to be stained or labeled

• Most subcellular structures, including organelles (membrane-enclosed compartments), are too small to be resolved by an LM

* LIGHT = LIVING ORGANISMS!

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The Cell

- Electron Microscopes- resolve down to 1 nm

- Scanning Electron (SEM)- Scans surface of object

The Cell

- Electron Microscopes- resolve down to 1 nm

- Scanning Electron (SEM)- Scans surface of object

- Transmission Electron (TEM)- Transmits electrons through object

Electron microscopes

Electron microscopes (EMs) • used to study subcellular structures

• Scanning electron microscopes (SEMs) focus a beam of electrons onto the surface of a specimen, providing images that look 3-D (SCANNING = SURFACE)

• Transmission electron microscopes (TEMs) focus a beam of electrons through a specimen

• TEMs are used mainly to study the internal structure of cells

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The Cell

- Cell Fractionation- Take the cell apart and separate the organelles by weight

- Completed by using an (ultra) centrifuge

- The heaviest organelles settle out first, the lightest settle out last

1) nuclei 2) mitochon/chloro.lysosomes 3) E.R./cell membrane

4) ribosomes

The Cell

• ALL cells have

- Chromosomes (genetic material)

- Ribosomes

*PROKS AND EUKS!

Eukaryotes

• Eukaryotes- “True kernel”. Has a nucleus. Large (10-100 um)

- Internal membrane for compartmentalizing functions

- Bound by plasma membrane

Eukaryotes

• Eukaryotes- “True kernel”. Has a nucleus. Large (10-100 um)

- Internal membrane for compartmentalizing functions

- Bound by plasma membrane

- Fluid inside of the cell is called cytosol

- The region between the nucleus and plasma membrane is the cytoplasm

Q.Q. 9/4/18Which cellular structure is common to all 3 domains of life?

a) Nucleusb) Endoplasmic reticulumc) Mitochondriad) Phospholipid bilayer cell membranee) Endocytotic vesicles

Q.Q. 9/4/18Which cellular structure is common to all 3 domains of life?

a) Nucleusb) Endoplasmic reticulumc) Mitochondriad) Phospholipid bilayer cell membranee) Endocytotic vesicles

Prokaryotes

• Prokaryotes- “Before kernel”. No nucleus. Small (1-10 um)

- Bound by plasma membrane

The Cell

• Limitations of cell size

- Restricted by metabolic requirements

(moving stuff in and out!)

- A small cell will have a proportional volume to surface area

- If the cell were to grow too large, then the volume will increase disproportionately (larger) than the surface area

Why are cells so small?!?

Simulation Lab: Surface Area to Volume Ratio

• 3 different size cells

Which size is more efficient in moving materials through the cytoplasm?

The Cell- In order to increase the surface area, many

cells have villi (finger-like projections)

Cell Membrane

• The plasma membrane is composed of a phospholipid bilayer *CH. 7

- Many proteins are embedded in the plasma membrane

Organelles

• Nucleus- Library of the cell because it contains most of the cells genes

• A nuclear envelope encloses the nucleus

- Double membrane

- Has pores that are regulated by pore complexes

Organelles

- Nuclear lamina- A net-like structure on the inside of the nucleus that provides mechanical support (constructed of proteins)

- Nuclear matrix- Framework inside of the nucleus for additional structural support

- Nucleolus- RNA is synthesized here; ribsomes made here

Ribosomes

• Protein synthesis “Ribs=proteins”

- Two types

1) Free ribosomes- in cytosol

Proteins constructed by these are usually used in the cytosol

Ribosomes

2) Bound ribosomes- Attached to outside of endoplasmic reticulum and nuclear envelope

- Proteins constructed by these usually incorporated into membranes and used for packaging and export.

Organelles

- Free ribosomes and Bound ribosomes can switch back and forth from one to another depending on cellular needs.

Endomembrane System

● includes the following:○ Smooth Endoplasmic Reticulum○ Rough Endoplasmic Reticulum○ Golgi Apparatus (complex, bodies)○ Lysosomes○ Vacuoles

● Has close ties to plasma membrane; think to have infolded over time to form

Endoplasmic Reticulum

• Biosynthetic factory "plasmic"= w/ in cytoplasm, "reticulum"= little net

• Accounts for more than half of the total membrane in many Euks.

• Network containing tubules and sacks called "cisternae" (reservoir)

• Internal compartments of the cisternae are called the "lumen" (cavity)

– 2 types • smooth and rough

Smooth ER

1) Smooth ER- no ribosomes

• Synthesis of lipids (oils, steroids, phospholipids)

• Metabolism of carbs• Detoxification of drugs/ poisons (especially in

liver cells. *There will be an abundance of smooth ER when many toxins are present)

• Storage of calcium ions (Ca+2)

Rough E.R.

2) Rough ER- HAS ribosomes• Construction of proteins and glycoproteins

(a carbohydrate is bonded to a protein)• Proteins can leave "wrapped up" in transport

vesicles and travel to Golgi Apparatus • Transport vesicles come from a piece of

rough ER• Makes additional membranes for itself and

other organelles

Golgi Apparatus• Shipment, protein modification• Transport vesicles arrive (cis end), contents

are dropped off and then shipped out again (trans end)

• Common in secretion cells (like pancreas cells that making secretory proteins)

• Composed of flat sacks (cisternae) in stacks “PANCAKES”

Golgi Bodies

The two opposing sides of the Golgi bodies have distinct polarities

Cis- nearest the ER

- Transport vesicles fuse to this side and then incorporate goods

- Trans- Vesicles pinch off and move around cell

*Alphabetically- C before T!

nearest Rough ER

Golgi Bodies

• Modification of goods in Golgi apparatus happens during transit from the cis to the trans side

• produce a limited amount of macromolecules (polysaccharides)

• Cisternal maturation model- actual cisternae progress from cis to trans side

• Goods are shipped with "tags" that will only bind to specific sites

Q.Q. 9/5/18

Which of the following does NOT contain functional ribosomes?

a) Rough ERb) nucleolusc) prokaryotic celld) animal mitochondrione) plant chloroplast

Q.Q. 9/5/18

Which of the following does NOT contain functional ribosomes?

a) Rough ERb) nucleolusc) prokaryotic celld) animal mitochondrione) plant chloroplast

What end of the Golgi receives packages?

What end of the Golgi ships out packages?

Cis end

Trans end

Lysosomes

• Empty compartments (bubbles) for intracellular digestion

• Contains enzymes that digest macromolecules• Membranes of the lysosome are made by the

rough ER, transferred to the Golgi apparatus, and are then "budded" off of the trans face

• Can digest the host cells organic waste or entire non-functioning organelle = autophagy and then re-use organic goods

*Phagocytosis animation -use of lysosomes in white blood cells to digest bacteria

Vacuoles

• Storage- cell can have one or many.• Can carry out hydrolysis• Food vacuoles come from phagocytosis• Contractile vacuoles pump out excess water

Central Vacuole

• In plants• Surrounded by a membrane called the

tonoplast• Can hold reserves of organic goods (proteins,

carbs, etc. • Repository of inorganic waste

(Water, dissolved salts, ions)

ENERGY ORGANELLES:Mitochondria/ Chloroplasts

○ Converts energy from one form to another○ Enclosed by membrane, but are NOT part

of the endomembrane system○ Contain their own DNA, but often still use

proteins from the cytosol (proteins constructed by nuclear transcription)

Mitochondria

• Energy,proteins (they house some ribosomes)*ATP Synthesis; powerhouse of cell; cellular respiration

• Has two membranes, each is a phospholipid bilayer

• Outer membrane is smooth

• Inner membrane is heavily

folded

(folds are called cristae)

● Mitochondrial matrix- the inside of the inner membrane○ Where majority of "work" takes place

Chloroplast

• Photosynthesis takes place here! • Light TO Sugar (glucose) energy• A plastid• Two membranes• Inner membrane connected to sacks =

Thylakoids “mentos”– Stack of Thylakoids = grana– Fluid outside of grana = stroma

(contains DNA/ Ribosomes)

Peroxisomes

• Oxidation• Metabolic component bound by a single

membrane *bubble like a lysosome• Contains enzymes that break down

molecules and produce hydrogen peroxide (H

2O

2)

• Hydrogen peroxide is toxic to cells, but a local enzyme breaks down H

2O

2 to water

Cytoskeleton

• Framework that organize structures and activities

• Mechanical support/ Shape• Motility- Motor proteins used to help cell change

shape- Can act like a "monorail" and transport

goods

Cytoskeleton• Regulation of biochemical activities• Can transmit an outside force to the inside of

the cell allowing for re-arrangement of organelles

• Three types: microtubules, microfilaments, intermediate filaments

Cytoskeleton

1) Microtubules- in all Euks (not in Proks). Crush resistant.

- Hollow rods but fairly thick- Composed of globular protein =

Tubulin (2 types)- Alpha Tubulin- Beta Tubulin

- Proteins are added to ends in order for elongation to take place

Cytoskeleton- Microtubules

• Centrosomes and Centrioles

- Microtubules originate from a centrosome (the centrosome is a REGION, and there is a PAIR of centrioles in the centrosome region)

- Centrioles replicate when cell replicates *MITOSIS/MEIOSIS

“Churros” = Centrioles

Cytoskeleton- Microtubules

• Cilia and Flagella- microtubules cause the movement; 9 + 2 arrangement in Euks. – 9 doublets or microtubules in a ring and 2

single microtubules in the center– Motor proteins BETWEEN the

doublets (called dynein) are what actually cause the movement with input of ATP

• Proteins hold structure together• Connected to cell at the basal body

CiliaFlagella- see movement at 0:40 secs

Flagella in Prok. vs. Euk.

Cytoskeleton- Microfilaments

2) Microfilaments- also called actin filaments (composed of actin proteins)

Solid rods, but small diameter• Twisted, double chain of actin • Made to bear tension (ie: pull)

- Main component of muscle

-Interwoven with another protein called myosin (motor protein) “myo”=muscle

• Active in amoeboid movement

Cytoskeleton- Intermediate Filaments

3) Intermediate Filaments- Somewhere between the size of the microtubules and microfilaments

• Tension bearers ; *cells requiring A LOT of strength!

• Composed of fibrous proteins of all sorts• A more permanent structure than the

previous structures (microtubules and microfilaments)

• Reinforces the cells shape; SCAFFOLDING

Cell Wall

• Protects, gives shape and keeps cell "water tight"

• Composed of cellulose matrix (w/ proteins)• Primary cell wall built when cell is "young",

but eventually it will either harden or a secondary cell wall will be built

• Middle lamella is a sticky substance that holds the cells together

Extracellular Matrix

• Extracellular matrix of animal cells- immediate outside of cell

- Composed of glycoproteins

- Collagen strong fibers

- Fibronectin- bind to surface receptors called integrins (transmits stimuli from the outside of the cell to the inside)

Intercellular Junctions

• Intercellular Junctions- Communication of neighboring cells

Plants

- Plasmodesmata- pores that cytosol can pass through

*like Gap junctions

in animals!

Intercellular Junctions

Animals

• Tight junctions- Prevents "leaking" from between cells

• Desmosomes (Anchoring junctions)- "Rivets" that hold the cells together

• Gap junctions- Cytoplasmic channels for communication between cells

Which of these organelles are absent in plant cells?

a) mitochondriab) centriolesc) microtubulesd) all of the abovee) none of the above

Which of these organelles are absent in plant cells?

a) mitochondriab) centriolesc) microtubulesd) all of the abovee) none of the above

Endomembrane System

A membrane protein synthesized in the rough ER may be directed to

a) peroxisomes.b) lysosomes.c) mitochondria.d) all of the above

Endomembrane System

A membrane protein synthesized in the rough ER may be directed to

a) peroxisomes.b) lysosomes.c) mitochondria.d) all of the above

According to the endosymbiont theory, which of the following organelles were once endosymbiotic prokaryotic organisms?a) Mitochondria and lysosomesb) Mitochondria and chloroplastsc) Chloroplasts and Golgi apparatusd) Golgi apparatus and ribosomes

According to the endosymbiont theory, which of the following organelles were once endosymbiotic prokaryotic organisms?a) Mitochondria and lysosomesb) Mitochondria and chloroplastsc) Chloroplasts and Golgi apparatusd) Golgi apparatus and ribosomes

Which of the following is not an argument for the theory that mitochondria and chloroplasts evolved from prokaryotic endosymbionts? a) Mitochondria and chloroplasts have double

membranes.b) Mitochondria and chloroplasts have their own

ribosomes.c) Mitochondria and chloroplasts have their own DNA.d) The mitochondrial and chloroplast genomes are

circular.e) All of the above support the endosymbiotic theory.

Which of the following is not an argument for the theory that mitochondria and chloroplasts evolved from prokaryotic endosymbionts? a) Mitochondria and chloroplasts have double

membranes.b) Mitochondria and chloroplasts have their own

ribosomes.c) Mitochondria and chloroplasts have their own DNA.d) The mitochondrial and chloroplast genomes are

circular.e) All of the above support the endosymbiotic theory.

Taxol, a drug approved for treatment of breast cancer, prevents depolymerization of microtubules. What cellular function that affects cancer cells more than normal cells might taxol interfere with?

a) maintaining cell shapeb) cilia or flagellac) chromosome movements in cell divisiond) cell division (cleavage furrow formation)

Taxol, a drug approved for treatment of breast cancer, prevents depolymerization of microtubules. What cellular function that affects cancer cells more than normal cells might taxol interfere with?

a) maintaining cell shapeb) cilia or flagellac) chromosome movements in cell divisiond) cell division (cleavage furrow formation)