BCHM3050-2.pptx

(1)

(2)

(3)

Figure 2.7

Typical

Bacterial Cell



Prokaryotes include bacteria and archaea



They have cell wall, plasma membranes, circular

DNA, and no membrane-bound organelles-

lack

a

membrane bound nucleus

(4)

Structure of Prokaryotic Cells

Figure 2.8

Bacterial Cell

(5)



Cell Wall



The prokaryotic cell wall is a complex

semi-rigid structure primarily for support

and protection



The cell wall is primarily composed of

peptidoglycan

Cell Wall and Plasma Membrane

www.torresbiocla.pbs.com

(6)

PlasmaMembrane



Biological Membranes



Thin, flexible, and stable sheet-like structures



Selective physical barrier



Phospholipid bilayer with

integral

and

peripheral

membrane proteins

Figure 2.3 Membrane

Structure

(7)

Figure 2.10 Bacterial

Cytoplasm



Cytoplasm



Prokaryotic cells do have

functional compartments



Nucleoid

, which is centrally

located and contains the

circular

chromosome



Also contains small

DNA

plasmids



Inclusion

bodies

are large

granules that contain organic or

inorganic compounds

(8)

CHROMOSOME

PLASMID

Plasmid

• Can replicate independently of chromosomes

(9)



Many bacteria have external appendages



Pili (pilus) are for attachment and conjugation



Flagella (flagellum) are used for locomotion

(10)

Figure 2.11 Animal

Cell



Eukaryotic cells are structurally complex



Membrane-bound organelles and the

endomembrane system

increase surface area

for chemical reactions

Animal Cell

(11)



Important structures: plasma membrane,

endoplasmic reticulum, Golgi apparatus,

nucleus, lysosomes, mitochondria,

chloroplasts, ribosomes, and the cytoskeleton

Plant Cell

Figure 2.12 Plant

(12)



Plasma Membrane



Isolates the cell and is selectively permeable



Outside the plasma membrane are the

glycocalyx

and the

extracellular matrix

Plasma Membrane

Figure 2.13

Plasma

Membrane

(13)



Endoplasmic Reticulum



The

endoplasmic reticulum

(ER)

is a series of membranous

tubules, vesicles, and flattened

sacks



Two types:



Rough ER

functions include

protein synthesis, folding, and

glycosylation



Smooth ER

functions include

lipid biosynthesis and Ca

2+

storage

Endoplasmic Reticulum

Figure 2.15

Endoplasmic

(14)

Ribosomes

Figure 2.29

Ribosomes



Ribosomes



Ribosomes

are RNA/protein

complexes involved in protein

biosynthesis



Two subunits form a functional

unit



Eukaryotes and prokaryotes

have ribosomes



Eukaryotic ribosomes are larger

than prokaryotic ones although

they are similar in structure and

function



In eukaryotes RER consists

of ribosomes attached to the

ER

(15)



Golgi Apparatus



The

Golgi apparatus

is

formed of large,

flattened, sac-like

membranous vesicles



Processes, packages,

and distributes cell

products



Participates in

EXOCYTOSIS

Golgi Apparatus

(16)



Nucleus



The

nucleus

is the most

prominent organelle



Contains the hereditary

information ( DNA)



Site of

transcription



Nuclear components:



Nucleoplasm



Chromatin

(

genome

)



Nuclear

matrix



Nucleolus



Nuclear envelope

Nucleus

Figure 2.18 Eukaryotic

(17)



The

nuclear envelope

surrounds the nucleoplasm



The nuclear envelope has

nuclear pores

referred to as

nuclear pore complexes



Structures through which

pass most of the

molecules that enter and

leave the nucleus

Nuclear Envelope

(18)

Lysosomes

Figure 2.21 Lysosomes



Vesicular Organelles



Lysosomes

are vesicles that

contain digestive enzymes



Enzymes are acid hydrolases



Degrade debris in cells and

involved in

autophagy

(19)

Mitochondria

Figure 2.23 The Mitochondrion



Mitochondria



The

mitochondria

(mitochondrion)

are

recognized as the site of

aerobic metabolism



Mitochondria are the

principle source of cellular

energy (ATP)



Have

inner

and

outer

membrane

surrounding

the

matrix

(20)

Peroxisomes



Peroxisomes



The peroxisome is a

small organelle containing

oxidative enzymes



Detoxifies peroxides

(e.g., H

2

O

2

)

(21)

Plastids

Figure 2.25

Chloroplast



Plastids



Plastids

are organelles

found only in plants, algae,

and some protists



Two types:

leucoplasts

and

chromoplasts



Chloroplasts

are

chromoplasts specialized for

(22)

Cytoskeleton



Cytoskeleton



The

cytoskeleton

is an intricate supportive

network of fibers, filaments, and associated

proteins



Three main components:



Microtubules

(largest) (contains the protein

tubulin

)



Microfilaments

(smallest) (contains the protein

actin

)



Intermediate

filaments



Main functions include cell shape, structure, and

cell movement



Cilia and Flagella are made up of cytoskeletal

structures

(23)

• Microtubules: Made up of tubulin and tubulin-binding

Proteins ( kinensin and dynein)

• Microfilaments: Made up of actin and actin-binding proteins

( myosin, troponin, tropomodulin, actinin)

(24)

Cytoskeleton

Figure 2.26 The

Cytoskeleton

(25)

Cytoskeleton