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CHAPTER 3
CELL
PROCESSES
Chemistry of life
• Everything around you is made up of matter
and energy.
Matter- anything that takes up space
Energy- can hold matter or break it apart
Matter is made of atoms
- Its nucleus contains protons and neutrons
- Outside the nucleus are electrons, which are involved
in a chemical reaction
Elements- made up of only one type of atom
- They cannot be broken down into simpler forms
by ordinary chemical reactions.
- Arranged in a chart called the periodic table of
elements
COMPOUNDS- molecular and ionic
- Made of two or more elements in exact proportions
- Have different properties from the element they are
made of
- The smallest part of a molecular compound is called a
molecule
* A molecule is a group of atoms held together by the
energy of chemical bonds. They form when atoms share
electrons.
Ionic compound-Ions- electrically charged atoms, positive or
negative
- Ions of opposite charges attract one another to
form electrically neutral compounds
MIXTURE- combination of substances in which
individual substances keep their own properties.
Solution- mixture in which two or more substances
are mixed evenly.
Suspension- forms when a liquid or gas has another
substance evenly spread throughout it
ORGANIC COMPOUNDS
- Contains carbon and hydrogen and are usually
associated with living things or things that were once
alive; four groups of organic substances make up all
living things.
1. Carbohydrates-supply energy for cell processes
2. Lipids- store and release large amounts of energy
3. Proteins- the building blocks of many structures
- amino acids- smaller molecules that make
up proteins
-enzymes- proteins that regulate all activities
in the cell
4. Nucleic Acids- store important coded information in
cells
INORGANIC COMPOUNDS
• Usually made from elements other then
carbon
THE IMPORTANCE OF WATER
-Living things are composed of more then 50%
of water and depend on it to survive.
-All chemical reactions in living things take place
in water solutions
- Most living things use water to transport
materials throughout their bodies/
What are we made of?
• Organic compounds, including carbohydrates,
lipids, proteins and nucleic acids. Also
inorganic compounds, like water. On a smaller
level, these compounds are made of
elements, which are made of atoms
Moving molecular material
• Cells have a selectively permeable membrane
that regulates what goes into and out of the cell.
PASSIVE TRANSPORT- the movement of
substances through a cell membrane without the
input of energy
Diffusion- when molecules move away fromarea
where there are more of them into areas where
there is fewer of them; stops when the molecules
of one substance are spread evenly throughout
another substance, and EQUILLIBRIUM occurs.
Osmosis- the diffusion of water through a cell
membrane
In Fascilitated diffusion-transport proteins move
substances into or and out of the cell .
Active TransportRequires energy to move a substance through
a cell membrane
ENDOCYTOSIS AND EXOCYTOSIS
-endocytosis- the process in which a substance
is taken into a cell by surrounding it with the
cell membrane, form in a sphere called a
vesicle.
-exocytosis- the process in which the membrane
of the vesicle fuses with the cell membrane
and the vesicle’s contents are released outside
the cell.
What need’s to be transported in your
body?
• Nutrients form food, and water needs to be
transported into a cell; wastes and carbon
dioxide need to be transported out of a cell.
ENERGY FOR LIFE
• Cells use chemical reactions to change the
chemical energy stored in food into forms
needed to perform activities
Metabolism- the total chemical reactions in sn
organism
- The chemical reactions of metabolism require
enzymes
Photosynthesis
• The process that plants and other organisms use
to convert light energy into chemical energy or
sugars to be used as food.
- Producers- organisms that make their own food
- Consumers- organisms that cant make their own
food
* Cholorophyll and other pigments are
Used in photosynthesis to capture light
Energy which is used to produce sugar
And oxygen.
Respiration
• The process in which chemical reactions break down
food molecules into simpler substances and released
stored energy.
1. Respiration of carbohydrates begins in the cytoplasm
- Carbohydrates are broken down into glucose
molecules
- Each glucose molecule is broken down into two
simpler molecules, releasing energy.
2. Respiration moves into the mitochondria
-The two simpler molecules are broken down again,
releasing much more energy
-the process uses oxygen and produces CO2 and water as
wastes.
FERMENTATION
• Cells that do not have enough oxygen for
respiration use this process to release some of
the stored energy in glucose molecules.
- entire process occurs in the cytoplasm
-
Fermentation
Produces lactic acid, alcohol, and carbon
dioxide as wastes
Photosynthesis and respiration
• THE OPPOSITE OF EACH OTHER
-Photosynthesis produces sugars and oxygen,
which are used in respiration
-respiration produces carbon dioxide and water,
which are used in photosynthesis
Cell reproduction
• Cell division- Increases the number of cells
that may cause many celled organisms to
grow.
The cell cycle
- The cells have periods of formation, growth
and development, and death called life cycles.
- Interphase- most of life in any eukaryotic cell,
or cell with a nucleus, is spent in a period of
growth and development
- During interphase, a cell duplicates its
chromosomes and prepares for cell division
- After interphase, the nucleus divides, and the
cytoplasm seperates to form two new cells
MITOSIS
• Process in which the nucleus divides to form two
new nuclei
1. Chromosome- structure in the nucleus that
contains hereditary material
2. Prophase
-the nucleolus and nuclear membrane
disintergrate
- centrioles move to opposite ends of the cell
Spindle fibers begin to stretch across the cell
Metaphase
- Pairs of chromatids line up accross the center
of the cell.
Anaphase
-each centromere divides
- Each pair of chromatids separates and moves
to opposite ends of the cell
Telophase
- Spindle fibers disappear and a new nucleus
forms.
Division of the cytoplasm- for most cells the
cytoplasm separates after the nucleus divides
- In animal cells, the cell membrane pinches in the
middle and the cytoplasm divides.
-In plant cells, a cell plate forms
mitosis
Results of Mitosis
• Each cell in your body, except sex cells, has a
nucleus with 46 chromosomes
• Allows growth and replaces worn out or
damaged cells.
Asexual Reproduction
- An organism with no nucleus divides into two
identical organisms by fission.
- Budding- a small exact copy of the adult grows
from the body of the parent
- Regeneration- a whole new organism grows
from each piece of the parent
FISSION
BUDDING
REGENERATION
SEXUAL REPRODUCTION AND MEIOSIS
• Sexual reproduction- two sex cells, usually an
egg and a sperm, come together.
Fertilization- the joining of an egg and a sperm,
generally from two different organisms of the
same species.
• Sperm are formed in the male reproductive
organs.
• Eggs are formed in the female reproductive
organs.
A zygote forms from fertilization of a sperm and
egg.
Following fertilization, cell division begins and a
new organism develops.
Human body cells are DIPLOID because they contain
23 PAIRS of similar chromosomes.
Human sex cells are HAPLOID because they have 23
SINGLE chromosomes’
MEIOSIS
• A process that produces haploid sex cells and
ensures that offspring have the same diploid
number as its parent.
• 1. In meiosis1, the nucleus divides and
produces 2 new cells with one duplicated
chromosome each.
• 2. In Meiosis 2, the nuclei divide and the
chromatid separate, producing 4 cells with
half the number of chromosomes of the
original nucleus.
DNA
• A chemical that contains information that an
organism needs to grow and function
Watson and Crick developed an accurate model
of DNA in 1953
• The structure of DNA is similar to a twisted
ladder.
- The sides of the ladder are made up of sugar
phosphate molecules
- The rungs of the ladder are made up of
nitrogen bases
• Before a cell divides, its DNA duplicates itself
by unwinding and separating its sides, then
each side becomes a pattern which a new side
forms
GENES- section of DNA on a
chromosome
• Contain instructions for making specific proteins
RNA carries the codes for making proteins from the
nucleus to the ribosomes in the cytoplasm.
- Messenger RNA carries the code that directs the
order in which the amino acids bond
- Ribosomal RNA makes up the ribosomes, where
proteins are built
- Transfer RNA bring amino acids to the ribosomes
to build the protein.
Cells use only the genes that direct the making of
proteins needed by that cell.
MUTATIONS
• Any permanent change in the DNA sewuence
of a cell’s gene or chromosome
- Can be caused by outside factors like x-rays,
sunlight, and chemicals.
- A change in a gene or chromosome can
change the traits of an organism
Some examples of mutations