Transcript Cell structure and function

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The cell is the basic unit of life – It is a
structure within a living thing that has a
definite boundary enclosing the material
inside
Discoveries of Robert Hooke, Matthias
Schleiden, and Theodore Schwann led to the
discovery of cell theory
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Cell theory states that:
◦ All living things are made up of cells
◦ Cells are the basic unit of structure and function
within living things
◦ New cells are made from existing cells
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All functions of the cell are based on different
chemical reactions
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Cells generally range from 5-50 micrometers
in diameter and typically can only be seen
using a microscope
These cells fall into 2 categories depending
on whether they have a nucleus or not
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Prokaryotes make up what we call bacteria
They are characterized by their lack of a
defined nucleus (The cell structure that
contains the cells DNA or genetic material)
The genetic material is still present within
the cell
Prokaryotes are generally simpler than
eukaryotes but they are able to carry out
every activity associated with living things
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Eukaryotes are generally larger and more
complex than prokaryotes
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Eukaryotes contain a nucleus that separates
the DNA from the rest of the cell
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Eukaryotic cells range from making up single
celled organisms to multicellular organisms
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A cell is made up of many parts with different
functions that work together. Similarly, the parts of
a computer work together to carry out different
functions.
Working with a partner, answer the following
questions.
1. What are some of the different parts of a
computer? What are the functions of these
computer parts?
2. How do the functions of these computer parts
correspond to the functions of certain cell parts?
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Cells are similar to little factories – They are
made up of small “machines” that each have
certain functions – These are called
organelles – Tiny structures within a cell that
carry out cell functions
The organelles of a cell are divided into 2
areas, the nucleus and the cytoplasm
Prokaryotic and Eukaryotic Cells
Section 7-1
Cell membrane
Cytoplasm
Prokaryotic Cell
Cell membrane
Cytoplasm
Nucleus
Eukaryotic Cell
Organelles
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This is the part of the cell that separates the
genetic material from the rest of the cell – It
is also where the information for protein
building comes from
The nuclear envelope surrounds the nucleus –
This is made up of 2 membranes, designed to
allow certain materials into and out of the
nucleus
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Within the nucleus, contained in
chromosomes, is the DNA (genetic
information)
Another structure in the nucleus is the
nucleolus – This is where the assembly of
ribosomes begins
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Ribosomes get their name because they are
made up of the 5 carbon sugar called ribose
Ribosomes are organelles that produce
proteins
The instructions on how these proteins are
made come from the nucleus, via the RNA
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This is where the lipid components of the cell
membrane are made – Also modified here are
proteins and some other material that gets
exported from the cell
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Rough ER gets its name from the ribosomes
covering its outer surface, giving it a “rough”
appearance
This is where proteins are modified
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Smooth ER gets its name from the lack of
ribosomes
One major purpose of the smooth ER is to
make lipids for the plasma membrane
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The proteins modified in the rough ER move
on to the Golgi apparatus – They are then
sorted, modified and packaged for storage
(within the cell) or secretion (outside the cell)
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Take a look at the Golgi apparatus and the ER –
Notice how alike they are in appearance – What are
the differences in function between the two?
Nucleolus
Nucleus
Ribosome
(attached)
Nuclear
envelope
Ribosome
(free)
Cell
Membrane
Mitochondrion
Smooth
endoplasmic
reticulum
Rough
endoplasmic
reticulum
Centrioles
Golgi apparatus
Animal Cell
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Lysosomes are small organelles filled with
enzymes
The purpose of these enzymes is to break
down lipids, carbohydrates, and proteins for
use in the cell
Another use for the lysosome is the removal
of old, used up organelles
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Vacuoles are generally used for storage of
materials such as water, proteins and
carbohydrates, but they are not present in every
cell
Plant cells contain a large, central vacuole, that also
helps with support
Some single celled organisms, like the
paramecium, have what is called a contractile
vacuole, which helps with movement
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Nearly all cells contain mitochondria
These organelles are said to be the
powerhouses of the cell
They convert chemical energy from food into
usable energy for the cell to use
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Most plant cells and some animal cells
contain organelles call chloroplasts
Chloroplasts are organelles that convert
energy from the sun into usable chemical
energy through a process called
photosynthesis
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This is a network of proteins that help the cell
maintain its shape
The cytoskeleton is made up of
microfilaments and microtubules
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Nucleolus
Nucleus
Chromosomes
Smooth ER
Lysosome
Mitochondria
Nuclear envelope
Ribosomes
Golgi apparatus
Rough ER
Vacuole
Cell membrane