Transcript Introduction to the Cell

Introduction to the
Cell
Chapter 7.1
Introduction to the Cell

Cell- smallest unit of matter that can
carry on all of the processes of life

Hooke and Leeuwenhoek used
microscopes to see first images of cells
in the 1600-1700’s.
The Cell Theory…
a. All living things are composed of cells
b. Cells are the basic units of structure
and function in an organism (smallest living
unit).
c. Cells come only from the reproduction of
existing cells (cells come from cells).
Cells Size…

Limited in size because of surface to
area ratio
– If a cell gets too big the nutrients and
wastes do not have enough surface area to
come into / out of the cell
Shape…

A cells shape is usually associated with
its job.
Internal Organization…

Cells contain many organelles
– Def: cell component that performs specific
functions for the cell
• Like mini organs
– Cell membranes surround cell and
decides what goes in and out of the cell.
– Nucleus contains genetic information
(DNA), which controls the cell.
Eukaryotic vs. Prokaryotic

Eukaryotic
– Cell that has
membrane bound
organelles
– More complex
– Plant and animal
cells
-YOU are a
eukaryote!

Prokaryotic
– Has membrane
around entire cell
– No organelles
– No nucleus
– bacteria
Eukaryotic vs. Prokaryotic
Bill Nye: Discovery of Cells
Organelles
Inside the Eukaryotic Cell
7.2
Cell Membrane

The lipid bilayer that surrounds the cell
Cell Membrane cont.
Controls what enters/leaves the cell
 Selectively permeable – allows some
substances to enter while not allowing
others to enter
 Sometimes have proteins integrated
into the layer, some are on either side of
the bilayer

All cells have:
Cytoplasm-a jelly like substance that
fills the cell within the cell membrane.
 Ribosomes- the cellular
structure where proteins
are made.

Nucleus

Contains DNA,
hereditary info.
 Surrounded by the
nuclear membrane
 Also has a nucleolus
where ribosomes
are made.
 The cell’s “brain.”
Mitochondria

Site of chemical
reactions that
produce ATP
(energy).
 Have folded center
to allow for more
surface area for
production of ATP
 Have their own DNA
 Many of them in the
cell
Ribosomes

Numerous; some
are free floating
others are attached
to Endoplasmic
Reticulum
 Play a large role in
the production of
proteins
Endoplasmic Reticulum

Act as highway for
proteins and other
substances, has
many different
channels
 Rough ER –
ribosomes make
proteins, ER ships
them off
 Smooth ER – makes
steroids, regulates
calcium, and breaks
down toxins
Lysosome

Uses enzymes to digest/break down organic
compounds, old cell parts and other materials
Golgi Apparatus

Processes and packages cells proteins
Cytoskeleton ~

Provides support and allows movement like a
human’s skeleton.
Cilia and Flagella
Cilia
 Found on outside of
the cell
 Aid in movement
 Hair-like structures
 Cilia are short and
come in large
numbers
Flagella
 Found on out side of
the cell
 Aid in movement
 Hair-like structures
 Flagella usually
come in 1-3.
Plant vs. Animal Cells
Both plants and animals have more
complex eukaryotic cells.
 However there are some differences in
there structure.

Plant Cells…

Have cell wall for
structural supportlike plant bones
 Has large vacuoles
for storage of water
and toxins
 Have Chloroplasts
that convert light
into chemical energy
Animal Cells

No cell wall, just a
cell membrane.
 No chloroplasts.
 No vacuole.
Levels of
Organization
From Cells to Organisms
7.3
Multicellular Organization
Cell
Tissue
Organ
Organ System
Organisms
Multicellular Organization
Cell=The smallest unit of life.
Tissue= A group of similar cells that are
working together. Examples: Muscle tissue
or bone tissue.
Organ= Similar tissues organized into a
structure with a specific function. Examples:
Heart, bones, liver.
Multicellular Organization
Organ system- Various organs working
together to carry out a major body function.
Examples: digestive system, urinary system,
reproductive system.
Organism-Any living thing that can carry out
life processes independently.