Transcript Basic Cell Structure

Basic Cell Structure
Cells
Basic building blocks of
life
Understanding of cell
morphology is critical to
the study of biotechnology
Cell
Smallest living unit of an
organism
Grow, reproduce, use
energy, adapt, respond to
their environment
Nucleus
Prokaryotes – have no
nucleus
Eukaryotes – have a
nucleus
Prokaryotes
Single celled organism
Kingdom Monera
Lacks a cell nucleus
Internal structure is less
organized than other cells
Common prokaryote
structures
Cytoplasm
Chromosomal material
Cell membrane and wall
Ribosomes
Some have flagellum for
mobility
Eukaryotes
Human body has at least
85 different cell types
All eukaryotes have a
number of structures in
common
Common structures
Organelles – smaller parts
of the cell with specific
funtions
Cell membrane – acts as
a gatekeeper
Cell membrane
Controls what enters and
leaves the cell
Plants, algae and bacteria
typically have a tough outer
structure known as a cell
wall
Cell wall
Provides additional structure
and protects the cell from
pressure caused by
movement of water
Animal cells do not have
walls
Cytoplasm
Organelles are surrounded
by a jelly like substance
Primary component is water
Other organelles
Ribosomes
Mitochondria
Golgi bodies
Endoplasmic reticulum
Nucleus
Contains DNA
DNA is located on
chromosomes
Most organisms are diploid –
have tow chromosomes for
each trait
Vacuole
Large organelle, without
specific shape
Store waste or raw materials
used in synthesis of proteins
Golgi Bodies
Adds modifications to
unfinished proteins
Makes Lysosome
Lysosome
Small round
Store enzymes that break
down food into chemical
compounds
Destroy cell organelles and
the cell itself
Mitochondria
Energy factories
Rod shaped
Change food into molecules
that can be used for energy
Cellular processes
Respiration
Osmosis
Diffusion
Photosynthesis
Respiration
Cells break down
carbohydrates and other
molecules to produce energy
Oxidation of glucose is one
of most common forms
Epithelial and Connective
Tissues
Epithelial tissues
Classes
 Junctions
 Glands

Connective Tissues
Matrix
 Cells
 Types

EPITHELIAL TISSUES
Sheets of cells
Specialized contacts/cell junctions (see below)
Basal lamina: protein scaffolding secreted by
epithelial cells
Basement membrane: reticular fibers (crossed
collagen network) that supports epithelium--really
associated connective tissue
Connective tissue support
Nutrients from capillaries in underlying connective
tissue
Nerves pass through
Easily regenerates
E.g. skin, lining of gut, mucous membranes
Classes of Epithelia
Simple: just one
layer or cell
shape
Stratified:
multiple layers
and cell shapes
Cell Junctions
Desmosome: binding spots between
cells with proteins called cadherins
Tight junctions: impermeable

E.g. gut tube, doesn’t let enzymes from gut
into blood stream
Gap junctions: tubes that let small
molecules pass between cells
Features of Apical Surface of
Epithelium
 Microvilli: (ex) in small intestine
 Finger-like extensions of the plasma membrane

of apical epithelial cell
Increase surface area for absorption
 Cilia: (ex) respiratory tubes


Whip-like, motile extensions
Moves mucus, etc. over epithelial surface 1-way
 Flagella: (ex)


spermatoza
Extra long cilia
Moves cell
Features of Lateral Surface of
Epithelium
Cells are connected to neighboring cells via:
Proteins-link cells together, interdigitate
 Contour of cells-wavy contour fits together
 Cell Junctions

Desmosomes-adhesive spots on lateral sides
 Tight Junctions-at apical area, plasma membrane of
adjacent cells fuse, nothing passes
 Gap junction-spot-like junction occurring anywhere, lets
small molecules pass

Cells of Connective Tissues
Fibroblasts make fibers
Immune cells in areolar tissue
Macrophages
 Plasma cells
 Mast cells
 Neutrophils, Lymphocytes

“Dense” Connective tissues
Irregular
Thick fibers running in many planes
 E.g. dermis, fibrous capsules around
organs

Regular
Aligned parallel fibers
 Resists tension
 E.g. tendon, ligaments, aponeuroses
 Sometimes with elastic fibers (e.g.
ligamentum nuchae)

Other Connective Tissues
Bone
Cartilage
Blood
Submitted by:
Jagmeetbir Singh
Angad Ahluwalia