Transcript Cells - Structure and Function

CELLS
Structure and Function
The Cell Theory and Cell Discovery
 The Cell Theory was developed
through the works of some key
scientists.

The cell theory states:
1)
all living things are made of one or
more cells.
2) all cells come from other cells.
3) cells are the basic units of structure
and function of living things.
The Cell Theory and Cell Discovery
 Scientists

contributions
Robert Hooke
1665
was observing cork under a
microscope.
Observed empty spaces, called
them “cells”.
Remember, cork comes from
trees, which are plants.
Cork is a dead organism.
The Cell Theory and Cell Discovery
 Scientists

contributions
Robert Brown
1883,
discovered the dark center
of the cell.
Called this the nucleus.
nucleus
The Cell Theory and Cell Discovery
 Scientists

contributions
Mathias Schleiden (1838)
Confirmed
that all plants are made
of cells.

Theodor Schwann (1839)
Stated
cells.
that all animals are made of
The Cell Theory and Cell Discovery
 Scientists

contributions
Anton van Leeuwenhoek (1674)
Observed

cells in greater detail.
Rudolf Virchow (1855)
Reported
cells.
all cells come from other
The Cell Theory and Cell Discovery
 Different types of cells….
 Plant cells – have cell walls &
chloroplasts.
 Animal cells – contain centrioles.

Prokaryotic -unicellular, no nucleus.
(DNA is suspended in the cytoplasm)

Eukaryotic – multi-cellular or unicellular,
cells have a nucleus.
(DNA is enclosed in the nucleus)
Animal Cells
1. Cell Membrane – PLASMA MEMBRANE
 Outermost part of the cell
 Gives the cell shape
 Holds everything inside
 Contains cellular pores which control
what can go in and out of the cell
2. Nucleus Located at the center of the cell
 Controls all of the cell’s activities, like a brain
 Determines when and what proteins are made.

3. Nuclear Membrane:
 Surrounds the nucleus
 Contains nuclear pores that allow certain
materials to move in and out of the nucleus
4. Nucleolus:
 Located inside of the nucleus
 Makes ribosomes
DNA – Deoxyribo Nucleic Acid
Genetic information made from chromosomes.
- Chromosomes are made of DNA,
chromosomes determine the traits of an
organism
The instructions or blueprints for making an
organism the way it looks.
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5. Canal network
(AKA… Endoplasmic reticulum)
– connects the nucleus to the cell membrane
- a passage way that helps
move materials within cell.
There are 2 types
Rough ER - when it
has ribosomes on it.
Smooth ER when there
are no ribosomes on it.
6. Ribosome:


Made by the nucleolus
Make proteins
Ribosomes are found in three places:
 In the Nucleolus
 On the Rough Endoplasmic Reticulum.
 Freely floating throughout the cytoplasm
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
7. Packaging structure –
AKA…(Golgi Apparatus)

– packs, stores and ships out proteins to the
cell membrane so they can be released from
the cell and distributed to the body.
8. Mitochondria:
 The “Powerhouses” of the cell because they
produce energy from digested food.

This is where the process of cellular
respiration occurs.
Cellular
respiration is a
process that breaks down
food into energy that can
be used by the cell.
9. Digestive sacs
AKS… Lysosomes:

– destroy worn out parts
and get rid of bacteria.
10. Vacuole:

Liquid-filled space that stores water, food,
and minerals

WHY are these organelles much larger in
plant cells
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Why is the vacuole larger in a
plant cell?


Because plants rely on rain in order to
receive water. Therefore the vacuole needs
to be much larger because the plant has to
be able to store its water for long periods of
time when there is no rain.
Without water a plant can not perform
photosynthesis!
11. Centrioles:



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Help with cell reproduction
Found in pairs
Arranged in 9 groups of 3
Only found in animal cells
12. Cytoplasm:


Clear, jellylike material between the cell membrane and
the nucleus that makes up most of the cell; holds
everything in place
Made mostly of water along with some other chemicals
Plant Cells

Plant cells have NO CENTRIOLES!

Have 2 additional organelles that are not
found in an animal cell.
 Cell Wall and Chloroplast
1. Chloroplasts:




Found only in plant cells
Necessary for photosynthesis
Contain the green pigment chlorophyll
Chlorophyll- traps sun’s energy,
plants use it for photosynthesis to make their own food.
2. Cell wall:




Found in plants, algae, fungi, and bacteria cells
It is a thick outer covering surrounding the cell membrane
Provides support and protection
Allows the stem of the plant to stand upright… for photosynthesis
D. Animal Cell Parts and Their Jobs
2. Nucleus
(entire structure)
4. Nucleolus
5. Chromosomes DNA
3. Nuclear Membrane
7. Ribosomes on er
7. Ribosomes in cytoplasm
1. Cell Membrane
9. Mitochondria
6. Smooth ER
6. Rough ER
11. Vacuole
3. Nuclear pore
12. Centrioles
8. Golgi
13 Cytoplasm
10.Lysosome
Plant cell
Vacuole
Smooth endoplasmic
reticulum
Ribosome
(free)
Chloroplast
Ribosome
(attached)
Cell
Membrane
Nuclear
envelope
Cell wall
Nucleolus
Golgi apparatus
Chromosomes
Mitochondrion

Take a Virtual Cell Tour
Rough endoplasmic reticulum
Nucleus
Cell Organization
 Unicellular

(single cell)
One cell carries out all of the
activities for the cell.
 Multicellular

(many cells)
Many cells work together to
allow an organism to function.
Cell Organization
Cells organize into tissue
Tissue organizes into organs
Organs organize into organ
… systems
Organ Systems organize
into living organisms.
Cell Processes
 Osmosis
and Diffusion.
The cell membrane has cellular
pores (openings) that allow
substances to enter or exit the
cell.
 The substance must
small enough to
fit though the pores

Cell Processes
 Osmosis
The movement of water across
the cell membrane.
 It flows from where there is a lot
to where there is a little.
 It flows until it reaches
equilibrium (balance)

Cell Processes
 Osmosis
Cucumbers placed in salt water:
water leaves the cucumber, the
cucumber shrivels up and becomes
wilted.
Cucumbers placed in 100 % pure
water:
water enters the cucumber and the
cucumber becomes plump
Cell Processes
 Diffusion
The movement of a substance
from where there is a lot to
where there is a little.
 It continues to move until it
reaches equilibrium (balance)

Cell Processes
 Diffusion
Sugar and Iodine molecules move
from one side of the tubing to the
other, but the starch molecules do
not; sugar molecules are smaller
than starch molecules so sugar
molecules fit through the pore
openings.
Cell Processes
 Hypertonic

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Hypotonic

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Greater % inside the cell
Water moves out, cell shrinks
Greater % outside the cell
Water moves in, cell swells
Isotonic

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Equal % inside and outside the cell
No movement, cell remains the same
ADD TO THE END OF YOUR
NOTES:
70 %
70 %
100%
Carrot has 70% purity
Distilled water has 100% purity
Water moves into carrot cells,
they swell and get larger
HYPOTONIC
50%
Carrot has 70% purity
Salt water has 50% purity
Water moves out of the carrot
cells, they shrink and get smaller
HYPERTONIC
70 %
70%
Carrot has 70% purity
The water has 70% purity
Water does not move into or out
of the cell, it is in equilibrium.
ISOTONIC
ADD TO THE END OF YOUR NOTES:
FYI TO UNDERSTAND  When Iodine mixes with
starch it will turn PURPLE color
Beginning of Demo
Water contains Iodine
(yellow/orange color)
Sack contains Sugar and Starch
(white color)
End of Demo
Water is fading in color
Sack has some purple color
inside of it.
Water is more yellowish maybe even clear
Sack is deeper purple
Water also has tested positive for sugar,
meaning sugar has gotten into the water.
Conclusion: Sugar molecules fit through the pores and moved from the sack to the beaker.
Iodine molecules fit through the pores and moved into the sack from the beaker (turned the
sack purple and faded the water. The starch molecules can not fit through the pores… if they
could they would have moved into the beaker of water turning it purple.