slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
● Organisms are either: Single-celled, such as most prokaryotes and protists or PowerPoint Presentation
Download Presentation
● Organisms are either: Single-celled, such as most prokaryotes and protists or

Loading in 2 Seconds...

play fullscreen
1 / 26

● Organisms are either: Single-celled, such as most prokaryotes and protists or - PowerPoint PPT Presentation


  • 88 Views
  • Uploaded on

The Microscopic World of Cells. ● Organisms are either: Single-celled, such as most prokaryotes and protists or Multicelled, such as plants, animals, and most fungi. The Microscopic World of Cells. How do we study cells?

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about '● Organisms are either: Single-celled, such as most prokaryotes and protists or' - lani-blevins


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

The Microscopic World of Cells

  • ● Organisms are either:
    • Single-celled, such as most prokaryotes and protists or
    • Multicelled, such as plants, animals, and most fungi
slide2

The Microscopic World of Cells

How do we study cells?

Light microscopes can be used to explore the structures and functions of cells.

slide3

The Microscopic World of Cells

● Electron Microscope

10 m

Human height

1 m

Length of some

nerve and

muscle cells

10 cm

Unaided eye

Chicken egg

1 cm

Frog eggs

1 mm

100 mm

Plant and

animal cells

Light microscope

10 mm

Nucleus

Most bacteria

Mitochondrion

1 mm

Smallest bacteria

Electron microscope

100 nm

Viruses

Ribosomes

10 nm

Proteins

Lipids

1 nm

Small molecules

Atoms

0.1 nm

Figure 4.3

slide4

The Microscopic World of Cells

TYPES OF MICROGRAPHS

Light Micrograph (LM)

(for viewing living cells)

Scanning Electron Micrograph (SEM)

(for viewing surface features)

Transmission Electron Micrograph (TEM)

(for viewing internal structures)

LM

Colorized TEM

Colorized SEM

Light micrograph of a protist, Paramecium

Scanning electron micrograph ofParamecium

Transmission electron micrograph ofParamecium

slide5

The Two Major Categories of Cells

● The countless cells on earth fall into two categories:

Prokaryotic cells — Bacteria and Archaea

Eukaryotic cells — Eukarya

protists, plants, fungi, and animals

● All cells have several basic features.

1. They are all bound by a thin plasma membrane.

2. All cells have DNA.

3. All cells have ribosomes.

Cytoplasm-the entire contents of a cell

slide6

Prokaryotic Cells

● Prokaryotes

Are smaller than eukaryotic cells

Lack internal structures surrounded by membranes

Lack a nucleus

Have a rigid cell wall

Plasma membrane

(encloses cytoplasm)

Cell wall (provides

Rigidity)

Capsule (sticky

coating)

Prokaryotic flagellum

(for propulsion)

Ribosomes

(synthesize proteins)

Nucleoid (contains DNA)

Pili (attachment structures)

Colorized TEM

slide7

Eukaryotic Cells

● Eukaryotic cells are fundamentally similar.

*Generalized plant cell

*Generalized animal cell

slide8

Membrane Structure

● The plasma membrane separates the living cell from its nonliving surroundings.

Proteins

Outside of cell

Outside of cell

Hydrophilic

region of

protein

Hydrophilic

head

Hydrophobic

tail

Hydrophilic

head

Phospholipid

bilayer

Hydrophobic

tail

Phospholipid

Cytoplasm (inside of cell)

(a) Phospholipid bilayer of

membrane

Hydrophobic

regions of

protein

Cytoplasm (inside of cell)

(b) Fluid mosaic model of

membrane

slide9

Membrane Structure

● Phospholipid structure

Phospholipids are amphipathic molecules

slide10

Membrane Structure

● The plasma membrane separates the living cell from its nonliving surroundings.

Proteins

Outside of cell

Outside of cell

Hydrophilic

region of

protein

Hydrophilic

head

Hydrophobic

tail

Hydrophilic

head

Phospholipid

bilayer

Hydrophobic

tail

Phospholipid

Cytoplasm (inside of cell)

(a) Phospholipid bilayer of

membrane

Hydrophobic

regions of

protein

Cytoplasm (inside of cell)

(b) Fluid mosaic model of

membrane

slide11

Membrane Structure

● Some functions of membrane proteins

Cytoplasm

Fibers of

extracellular

matrix

c

Enzymatic activity

b

Cell signaling

a

Attachment to

cytoskeleton and

extracellular

matrix

e

Intercellular

joining

f

Cell-cell

recognition

d

Transport

Cytoplasm

Cytoskeleton

● Cell surface – Extracellular Matrix

slide12

Nucleus

● The nucleus is an organelle that houses the genetic material of the cell.

Nuclear

envelope

Nucleolus

Chromatin

Pore

Chromatin

Nuclear envelope

Nucleolus

Nuclear Pore

TEM

TEM

Surface of nuclear

envelope

Nuclear pores

slide13

Chromatin

DNA molecule

Proteins

Chromatin

fiber

Chromosome

Figure 4.9

slide14

Ribosomes

● Ribosomes build all the cell’s proteins (protein synthesis)

Composed of proteins and Ribosomal RNA

Free: proteins for cytosol

Membrane-bound: proteins for

cell membranes and export

slide15

How DNA Directs Protein Synthesis

● DNA controls the cell by transferring its coded information into RNA

DNA

1

Synthesis of

mRNA in the

nucleus

mRNA

  • The information in the RNA is used to make proteins

Nucleus

Cytoplasm

mRNA

2

Movement of

mRNA into

cytoplasm via

nuclear pore

Ribosome

3

Synthesis of

protein in the

cytoplasm

Protein

slide16

The Endomembrane System

  • ● Many of the membranous organelles in the cell belong to the endomembrane system
the endoplasmic reticulum
The Endoplasmic Reticulum
  • Produces an enormous variety of molecules
  • Is composed of smooth and rough ER

Nuclear

envelope

Ribosomes

Rough ER

Smooth ER

the endoplasmic reticulum1
The Endoplasmic Reticulum

After the rough ER synthesizes a molecule it packages the molecule into transport vesicles

4

Transport vesicle

buds off

Secretory

protein inside

transport

vesicle

Ribosome

3

Protein

1

Rough ER

2

Polypeptide

the golgi apparatus
The Golgi Apparatus
  • Works in partnership with the ER
  • Refines, stores, and distributes the products of cells

Transport

vesicle

from ER

“Receiving” side of

Golgi apparatus

Golgi apparatus

New vesicle forming

Transport vesicle

from the Golgi

“Shipping” side of

Golgi apparatus

Plasma membrane

lysosomes
Lysosomes
  • It contains digestive enzymes
  • The enzymes break down macromolecules
  • A lysosome is a membrane-enclosed sac
  • They break down damaged organelles

Lysosome

Digestion

Damaged

organelle

(b) Lysosome breaking down damaged organelle

slide21

Vacuoles

Vacuoles are membranous sacs

slide22

Traffic of Large Molecules

  • Exocytosis is the secretion of large molecules within vesicles.

Outside of cell

Plasma

membrane

Cytoplasm

slide23

Traffic of Large Molecules

  • Endocytosis takes material into a cell within vesicles that bud inward from the plasma membrane.
slide24

Transport of large molecules

Exocytosis

Types of endocytosis found in animal cells:

Endocytosis

*Phagocytosis

*Pinocytosis

*Receptor-mediated endocytosis

slide26

The Endomembrane System

Rough ER

Transport

vesicle from ER

Golgi

apparatus

Secretory

vesicle from Golgi

Vacuole

Lysosome

Secretory

protein

Plasma membrane