Transcript Cell Processes and Energy

Cell Processes and Energy
Table of Contents
Photosynthesis
Respiration
Cell Division
Cancer
Cell Processes and Energy
Energy in Living Things
-Every living thing needs energy.
-The cells of living things need
energy too.
-The sun is the direct or indirect
source of energy for most
living things.
Cell Processes and Energy - Photosynthesis
The sun is
the direct
source of
energy.
The sun is
the source
of energy for
most living
things
The sun is the indirect
source of energy.
The zebra gets
energy from
eating grass.
Plants use energy
from the sun to
make food.
The lion gets energy
by feeding on the
zebra.
Cell Processes and Energy
Photosynthesis
-Photosynthesis is the process by which
a cell captures energy in sunlight and
uses it to make food.
-Autotrophs —organisms that make
their own food. Examples: Plants, some
protists, some bacteria.
-Two stages of photosynthesis:
Cell Processes and Energy - Photosynthesis
*Stage 1: Chlorophyll captures the
energy from sunlight.
Cell Processes and Energy
*Stage 2: The captured light
energy is used to produce
sugar and oxygen from
carbon dioxide and water.
Cell Processes and Energy
-Water (H2O) enters the plant through
the roots and travels to the leaves.
-Carbon Dioxide (CO2) enters the
plant through stomata in the leaves.
Cell Processes and Energy
-In the chloroplasts, water and carbon
dioxide undergo several chemical
reactions powered by the light energy.
-The products are glucose and oxygen.
-Glucose is used for food or stored in
other forms to be used later.
Cell Processes and Energy
-Some of the oxygen is used to
break down the glucose molecules and
release energy.
-The rest is released to the atmosphere
through the stomata.
Cell Processes and Energy
The Photosynthesis Equation
-Chemists use equations to summarize
chemical reactions.
-The equation for photosynthesis is:
light
energy
6CO2 + 6H2O
Carbon
dioxide
Water
C6H12O6 + 6O2
Glucose
Oxygen
Cell Processes and Energy
End of Section:
Photosynthesis
Cell Processes and Energy
Cellular Respiration
-Cellular Respiration is the process by
which cells obtain energy from glucose.
-The chemical bonds of the glucose
molecule are broken to release energy.
-All cells carry out respiration
continuously.
-Respiration happens in the
mitochondria.
Cell Processes and Energy
The Respiration Equation
-The equation for respiration is:
C6H12O6 + 6O2
6CO2 + 6H2O + energy
Glucose
Carbon
dioxide
Oxygen
Water
Cell Processes and Energy
Comparing Photosynthesis and Respiration
-Photosynthesis and respiration can be
thought of as opposite processes.
-During photosynthesis, plants use
carbon dioxide and release oxygen.
-During respiration, organisms use
oxygen and release carbon dioxide.
Cell Processes and Energy - Respiration
-This keeps the levels of both gases
constant in Earth’s atmosphere.
Cell Processes and Energy
End of Section:
Respiration
Cell Processes and Energy
Fermentation
-Fermentation provides energy for
cells without using oxygen.
*The amount of energy released
from each sugar molecule is
much less than the amount
released during respiration.
Cell Processes and Energy
Types of Fermentation
-Two types of Fermentation:
*Alcoholic Fermentation—occurs
when yeast break down sugars.
Alcohol, carbon dioxide and a
small amount of energy are the
products. Yeast is used by
bakers and brewers.
Cell Processes and Energy
*Lactic Acid Fermentation—occurs
during very hard exercise. Muscles
use oxygen faster than you can
replace it so fermentation begins to
supply additional energy.
Lactic acid is produced and causes
sharp pains.
Cell Processes and Energy
Cell Division
-Cells grow and divide through a process
called the Cell Cycle.
-Three main stages to the cell cycle:
*Interphase—a period of cell growth,
development, and DNA replication
*Mitosis—division of the nucleus
*Cytokinesis—cytoplasm (cell) division
Cell Processes and Energy
Cells in your body that
no longer divide,
such as nerve and
muscle cells, are
always in interphase.
Cells that actively
divide, such as your
skin cells go through
the entire cycle.
Striated muscle cells
Skin (cheek) cells
Cell Processes and Energy - Cell Division
This diagram shows
that cells spend
most of their time in
Interphase.
Cell Processes and Energy
Details of Interphase
-Growth: the cell grows to its full size.
-Replication: DNA is long, thin and
inside the nucleus. It is called
chromatin material and it begins to
make a copy of itself.
-Preparation: cell makes centrioles
that will be used in division.
Cell Processes and Energy
Interphase
Chromatin
material
Centrioles
Cell Processes and Energy
Details of Mitosis
-The nucleus and its contents divide
by the process of mitosis.
-Mitosis happens in phases:
*Prophase
*Metaphase
*Anaphase
*Telophase
Cell Processes and Energy - Cell Division
-In Prophase:
chromatin condenses to
form chromosomes.
They are short, thick
and double-stranded.
The nuclear membrane
disappears.
Spindle fibers form.
Cell Processes and Energy
Prophase
Cell Processes and Energy
Metaphase
-In Metaphase, chromosomes line
up in the middle of the cell and
attach to spindle fibers.
Cell Processes and Energy
Anaphase
-During Anaphase, the chromosomes
split and are pulled by spindle fibers
to opposite ends (poles) of the cell.
Cell Processes and Energy
Telophase
-During Telophase, the chromosomes
again become long and thin.
-Two new nuclei form and the cytoplasm
is ready to divide.
Cell Processes and Energy
Cytokinesis
-Cytokinesis (division of the cytoplasm)
occurs last, forming two new cells.
-The two new cells are called daughter
cells.
-They are identical to the first cell and
have the exact same number of
chromosomes.
Cell Processes and Energy - Cell Division
Cell Processes and Energy
Meiosis
-Gamete cells (sperm and egg cells) are
produced through a process known as
meiosis.
-Gamete cells are not identical to the parent
cell. They only have ½ the number of
chromosomes.
-Just like body cells, gamete cells pass
through interphase before they divide.
-Just like mitosis, meiosis happens in
phases. However, the cell divides twice.
Cell Processes and Energy
Phases of Meiosis
There are two divisions each with four phases.
First Cell Division
Second Cell Division
Prophase I
Prophase II
Metaphase I
Metaphase II
Anaphase I
Anaphase II
Telophase I
Telophase II
Human Chromosomes
Cell Processes and Energy
Prophase I and Metaphase I
In Prophase I, doublestranded chromosome
pairs come together.
In Metaphase I, the
chromosome pairs line
up in the middle of the
cell and attach to
spindle fibers.
Cell Processes and Energy
Anaphase I and Telophase I
In Anaphase I, chromosome
pairs separate; reducing the
number of chromosomes in
each new cell to one-half.
In Telophase I, the cell divides
into two cells. Chromosomes
are still double-stranded.
Cell Processes and Energy
Prophase II and Metaphase II
In Prophase II, the spindle
fibers reappear.
In Metaphase II, the
chromosomes line up
in the middle of the cell
and attach to spindle
fibers.
Cell Processes and Energy
Anaphase II and Telophase II
In Anaphase II, the
chromosome strands separate
and move towards the poles.
In Telophase II the cell divides for
the 2nd time. The nuclear
membrane reforms. Four
gamete cells have been
produced. Each with ½ the
number of chromosomes.
Cell Processes and Energy
- The Cell and Inheritance
Meiosis
End result is four gamete cells,
each with half the number of chromosomes
Cell Processes and Energy
Comparison:
Meiosis vs.
Mitosis
Cell Processes and Energy
Fertilization
-The full number of chromosomes is
restored during fertilization —the joining
of sperm and egg.
-Zygote- first cell of a new organism.
-Human gamete cells = 23 chromosomes
-Human zygote cell = 46 chromosomes
-After fertilization, a zygote goes through
mitosis and the organism develops.
Cell Processes and Energy
DNA
-Chromosomes are made of DNA
molecules
-DNA – deoxyribonucleic acid
*found in the nucleus of a cell
*controls the cell’s activities
through coded instructions.
*Often called: “The blue-print
for life”.
Cell Processes and Energy
*Its structure was
discovered in 1953
by James Watson
and Francis Crick.
Cell Processes and Energy
-DNA is described as a doublehelix (twisted ladder).
-The sides of the ladder are made
of alternating sugar molecules
and phosphate groups.
-The rungs of the ladder are
composed of four nitrogen bases:
Adenine (A) Thymine (T)
Guanine (G) Cytosine (C)
Cell Processes and Energy - Cell Division
“A” pairs with “T” “G” pairs with “C”
The order of these pairs determines
your characteristics. Its your
“genetic code”.
Cell Processes and Energy
These base pairs split when DNA copies
itself. The molecule unzips itself and each
strand is copied.
Making a new DNA
molecule is like
making a new zipper
using the old zipper
as a model. Watch!!
While a zipper only has
one kind of tooth, DNA
has four; A, T, C and G.
Cell Processes and Energy
The correct bases float
in from the cytoplasm
according to the pattern.
The end result is
two identical
DNA molecules.
The section of DNA that directs the making of a
specific protein is called a gene.
Cell Processes and Energy - Cell Division
Cell Processes and Energy
RNA
-RNA—ribonucleic acid: carries the
genetic codes for making proteins from
the nucleus to the ribosomes.
-It is single-stranded instead of doublestranded.
-Uracil (U) replaces Thymine (T)
Cell Processes and Energy
- The DNA Connection
Protein Synthesis
Click the Video button to watch a movie
about protein synthesis.
Cell Processes and Energy
-Two types are made:
*Messenger RNA (mRNA) —made
from DNA in the nucleus. It leaves the
nucleus and attaches to a ribosome. It
carries info for making a protein.
*Transfer RNA (tRNA) —helps
translate the message and assemble
the amino acids needed to make the
protein.
Cell Processes and Energy
- The DNA Connection
How Cells Make Proteins
During protein synthesis, the cell uses information from a
gene on a chromosome to produce a specific protein.
Cell Processes and Energy
- The DNA Connection
Protein Synthesis Activity
Click the Active Art button to open a browser window and
access Active Art about protein synthesis.
Cell Processes and Energy
mRNA
tRNA
Cell Processes and Energy
End of Section:
Cell Division
Cell Processes and Energy
What is Cancer?
-Cancer —a disease in which cells
grow and divide uncontrollably,
damaging the parts of the body
around them.
*Over 100 types of cancer
*Can happen in almost any part of
the body.
Cell Processes and Energy - Cancer
Cancer begins
when a mutation
occurs in a cell.
Cancer cells break off
and spread.
The mutated cell divides
over and over producing
a tumor.
Cell Processes and Energy
Treating Cancer
-Three methods:
1. Surgery—remove the tumor
2. Radiation—use beams of high
energy waves to kill cancer cells.
3. Chemotherapy—use drugs to kill
cancer cells.
Cell Processes and Energy
Preventing Cancer
-Three ways:
1. Don’t smoke
2. Eat healthy
3. Protect skin from bright sun
Cell Processes and Energy
End of Section:
Cancer