Download TAKS Objective #2

TAKS Objective #2
The student will
demonstrate an
understanding of the
organization of living
systems.
Cells
Vocabulary Terms to Know
• Cell – structural and functional unit of
all organisms.
• Cell theory – states three things, (1)
all living things are made up of cells,
(2) all cells come from other cells,
and (3) the cell is the basic
organizational unit of all organisms.
Prokaryotic cell – has no true nucleus
and no membrane bound
organelles. Usually unicellular
organisms like bacteria.
Eukaryotic cell – has a nucleus and
membrane bound organelles. Found
in most multi-cellular organisms like
humans, animals and plants.
Homeostasis – an organisms
ability to maintain its internal
environment.
Levels of Organization
Cell
Tissue
Organ
Organ
System
Important Organelles of the Cell
Name
Cell Wall
Description
Found in plant cells;
provides shape & support
Vacuoles
Stores food & water;
“pantry”; bigger in plants
Cell Membrane Semi-permeable membrane
that surrounds cell
Golgi Bodies
Flat stacks that synthesize,
package & distribute
proteins
Name
Mitochondria
Endoplasmic
Reticulum
(ER)
Description
“power house” of
cell; cellular
respiration takes
place here
Area of chemical
reactions; smooth
and rough ER
Nucleus
“brain” of the cell;
location of DNA
Ribosomes
Protein synthesis;
found on rough ER
Name
Description
Lysosomes
Digests old cell parts
and foreign bodies
Flagella
Whip-like projection
used for locomotion
Cilia
Hair-like protrusions
used for locomotion
Cytoplasm
Jelly-like substance
in the cell
Introduction
• Cells are the basic units of life
– Cells can only be observed under microscope
• Two basic types of cells:
Animal Cell
Plant Cell
Plant Cell
• Cell wall
– Made of cellulose
– Strong and rigid
– In plant cells only
Plant Cell
• Cell wall
– Protect and support
the enclosed
substances
– Gives shape to the cell
Plant Cell
• Cell wall
freely permeable
Anything can freely
pass through the
cell wall.
Plant Cell
• Cell membrane
– Lies immediately
against the cell wall
Selectively permeable
Plant Cell
• Cell membrane
– Controls the
movement of
materials into and
out of the cell
Plant Cell
• Cytoplasm
– Jelly-like substance
enclosed by cell
membrane
– Provides a place for
chemical reactions to
take place
Plant Cell
• Cytoplasm
– Contains organelles:
•e.g. chloroplast
•e.g. mitochondrion
Organelles

has specific functions

found in the cytoplasm
• Chloroplast
Plant Cell
– Contain the green
pigment chlorophyll
•Used to trap light
energy, to make food
by photosynthesis
Photosynthesis takes place
in the chloroplast.
Look for the stacks of coins in the
middle!
Plant Cell
• Mitochondrion
( powerhouse)
– For cellular
respiration
Mitochondria
Look for the cristae or
snake like folds in the
middle to identify
mitochondria
Plant Cell
• Vacuole
– Very large in plant cells
– Contains a solution of
chemicals (sugars,
proteins, mineral salts,
wastes, pigments)
Plant Cell
• Nucleus
– Controls the normal
activities of the cell
– Bounded by a
nuclear membrane
– Contains thread-like chromosomes
Plant Cell
• Nucleus
– Each cell has a fixed
number of chromosomes
• Chromosomes carry
genes
– genes control cell characteristics
vacuole
cytoplasm
Animal cell
nucleus
mitochondrion
glycogen
granule
cell
membrane
• No cell wall or
chloroplast
Similarities between plant cells
and animal cells
Both have a cell membrane surrounding the
cytoplasm
Both have a nucleus
Both contain mitochondria
Differences between plant cells
and animal cells
Animal cells
Plant cells
Relatively smaller in
size
Relatively larger in
size
Irregular shape
Regular shape
No cell wall
Cell wall present
Differences between plant cells
and animal cells
Animal cells
Plant cells
Vacuole small or absent
Large central vacuole
Sugar granules as food
Starch granules as food
Nucleus at the center
Nucleus near cell wall
Microscope
• Instrument for
observing small
objects
The cell as the basic unit of life
• Cell is the smallest unit of living
organisms
• Unicellular organisms are made of one
cell only
• Multicellular organisms are made of
many cells.
Plant Cell
Animal Cell
1. The endoplasmic reticulum is an organelle found in
animal cells. One of the main functions of the
endoplasmic reticulum is to carry materials from one
part of a cell to another. One way that the endoplasmic
reticulum helps maintain the body’s homeostasis is by
• A transferring energy from carbohydrates to ATP
• B using genetic information to manufacture muscle
proteins
• C transporting oxygen from the lungs to all parts of the
body
• D delivering hormones to the cell membrane, where
they can be secreted
Answer: C
2.
Answer: A
3. Which of the
following cannot
metabolize
nutrients?
Answer: G
4. What organelle in plants captures
light energy and converts it to chemical
energy?
a. nucleus
b. chloroplast
c. mitochondrion
d. cytoskeleton
Answer: B
5. If you observed a cell under a
microscope and noticed that it contained a
plasma membrane, cell wall, and
ribosomes, but none of the other
organelles, what could you conclude?
a. It is an eukaryotic cell.
b. It is a prokaryotic cell.
c. It is an animal cell.
d. It is damaged.
Answer: B
6. What is the difference between plant and
animal cells?
a. Plant cells contain a cytoskeleton and
animal cells do not.
b. None, they contain the same features.
c. Plant cells have a cell wall and
chloroplasts, animal cells do not. Plant cells
usually are larger and contain one large
vacuole. Animal cells contain centrioles.
d. Animal cells contain a nucleus. Plant cells
do not contain a nucleus.
Answer: C
7. Which organisms are composed of cells
that do not contain nuclei?
a. eukaryotes
b. prokaryotes
c. animals
d. plants
Answer: B
8. Which two organelles occur in plant
cells but not animal cells?
a. nuclear envelopes and nuclei
b. cell membranes and chromosomes
c. cell walls and chloroplasts
d. ribosomes and chloroplasts
Answer: C
Learning Check
9.What is the difference between a
prokaryotic and a eukaryotic cell?
Prokaryotes do not have a true nucleus; whereas
eukaryotes do have a true nucleus and other
organelles
10.Which organelles are found in plant
cells, but not animal cells?
Cell wall and chloroplasts
11.DNA is found in the
cell.
Nucleus
of the
Cellular Transport
In order for an organism to
maintain homeostasis, it must
be able to move things into and
out of its cells. This is the job
of the cell membrane.
The cell membrane is
semi-permeable, or porous (kind
of like a coffee filter, or
border patrol).
It regulates what goes into and out
of the cell.
How do things go in and out of
the cell membrane?
Two main ways things can cross
through the semi-permeable barrier:
– 1. Passive Transport
– 2. Active Transport
Passive Transport
• Does not require energy!!
– Think of it as if you were sliding down a
slide. Did it require any energy for you
to go down the slide? No!
• There are 3 types of Passive
transport:
– 1. Diffusion
– 2. Facilitated Diffusion
– 3. Osmosis
Let’s discuss what it means to move from
an area of high concentration to an area
of low concentration….
High
Concentration
Moving from the
top of the slide to
the bottom of the
slide would be like
moving from a high
concentration to a
low concentration.
Low
Concentration
Lots of People
High Concentration
of People!
Another Example
Only a few People
Low Concentration
of People!
All three types of passive
transport move from an
area of high
concentration to an area
of low concentration!
Think of a water slide……..
What would happen if we were all in our
bikinis and at the top of the water slide at
Schlitterbahn and they turned off the
water?
It would be kind of hard and probably even
hurt to go down the slide right?
Would it be easier if we used a piece of
carpet or something to help us go down
the slide?
It sure would!
Facilitated diffusion uses a protein
instead of a piece of carpet to
help things move across the cell
membrane!
Osmosis is most simply
put as the diffusion of
water.
The circle below represents a cell that
is in a solution. The solution
surrounding the cell is 98% water while
the solution in the cell is 95% water.
Which direction will the water move
across the plasma membrane?
98%
H2O
Answer: water
will move into
the cell.
95% H2O
Remember that water will move from an area of high
concentration to an area of lower concentration.
Which direction will the water move
across the plasma membrane?
Answer: water
will move out
of the cell.
88%
H2O
95% H2O
Active transport requires energy
to move substances from an
area of low concentration to high
concentration.
He’s using energy!
Let’s discuss what it means to move from
an area of low concentration to an area
of high concentration….
High
Concentration
This would be like
trying to climb up
the slide. That
would take energy,
just as active
transport does!
Low
Concentration
Learning Check
#1 The movement of substances into and
out of a cell without the use of energy is
called:
A. active transport
C. passive transport
B. endocytosis
C
#2 A type of membrane which allows only
certain molecules to pass through is
called:
A. permeable
C. freely permeable
B. semi-permeable
B
3. __________ is when water diffuses
across a selectively permeable
membrane.
a. Osmosis
b. Exocytosis
c. Endocytosis
d. Diffusion
Answer: A
Chemistry of the
Cell
Acids contains Hydrogen
– They are sour in taste, and release H+
ions in water.
– Ex: citric acid (lemons, oranges), lactic
acid in sour milk, HCl acid in your
stomach
– They can be poisonous and corrosive.
Bases are bitter in taste and
feel slippery.
They contain hydroxide ions (OH-) and will
dissolve fats and oils.
They too can be poisonous and corrosive
to the skin.
– Examples include: magnesium
hydroxide in MOM, aluminum hydroxide
in deodorant.
pH Scale
0
7
14
acid
neutral
base
Lemon juice
Water
ammonia
Proteins are the building blocks
of the cell. They consist of long
chains of molecules called
amino acids. Proteins are made
in the ribosome.
Each bead is an
amino acid, and a
chain of amino acids is
a protein (the whole
necklace with lots of
beads put together).
Nucleic acids are found in nucleus
of the cell.
Two types of nucleic acids:
• DNA – directs the activities of the cell
• RNA – involved in protein making
Carbohydrates supply energy
to the cell.
–Consist of sugar, starch and
cellulose
Cellular respiration is the
process of transferring
energy from glucose (sugar)
to the cell’s energy (ATP).
= Energy for the cell
(ATP)
Glucose
ATP (Adenosine TriPhosphate)
is the chemical energy supply
for all cells.
The cells energy!
What does the cell need to
make ATP?
The cells needs both glucose and
oxygen in the mitochondria in
order for ATP to be made.
What are the reactants
needed for cellular respiration
to take place?
glucose and oxygen
What are the products of
cellular respiration?
ATP, carbon dioxide, and
water
• Where is ATP made in the
animal cell?
–Mitochondria (the powerhouse)
• Where is energy made in the
plant cell?
–Chloroplast
Photosynthesis occurs when plants
trap sunlight and use the energy to
form sugars.
This happens in the leaves of the plants.
The leaf cell has many chloroplasts, which
are filled with a green pigment called
chlorophyll, which helps trap the sunlight.
The formula for photosynthesis:
Water
6 CO2 + 6 H2O + sunlight
Glucose (sugar)
C6H12O6 + 6 O2
Carbon Dioxide
Oxygen
What are the reactants needed for photosynthesis?
Carbon dioxide, water, and sunlight
What are the products of photosynthesis?
Glucose and oxygen
Learning Check
#1 What form of energy is used by
cells?
A. glucose
B. ATP
B
C. carbon dioxide D. energy
#2 What is required for
photosynthesis to take place? D
A. water
B. carbon dioxide
C. sunlight
D. all of these
#3 What is the function of the
mitochondria?
A. photosynthesis
B
B. cellular respiration
C. digest old cell parts
D. make food
#4 Which is a product of cellular
B
respiration?
A. oxygen
B. carbon dioxide
C. glucose
D. carbohydrate
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TAK Obj. 02
TEKS
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