Transcript A- The Life Processes

th
7 Grade Science
Living Systems
Organisms
I- Living Things Carry Out Life Processes
A- Organisms, (any living thing) share certain characteristics
that set them apart from nonliving things.
B- Life Processes:
1-Getting and using energy
a-Nutrition: Taking in food (ingestion) &
down into a usable molecule (digestion).
b-Transport: Move materials throughout organism.
c-Respiration: Releasing energy stored in food.
breaking it
2- Getting rid of wastes: Excretion
3- Respond to changes in the Environment:
(Stimulus causes a Response)
Regulation
4- Growth & Development: Changing food into more of themselves.
5- Reproduction: Making of more organisms of
the survival of the species.
same kind to ensure
The Cell Basic Unit of Life:
1- Cell Theory: States that all
organisms are made of cells or
of a cell, all cells
come from other cells.
2- Cells Vary:
a- size, shape, and arrangement.
b- Unicellular: one cell
c- Multicellular: many cells.
3- Parts and Function of Animal Cells
a- Cell Membrane: thin structure covering the
surface of the cell.
•Allows materials needed by cell to enter and wastes to
leave.
b- Cytoplasm: jellylike substance
that fills cell.
Contains proteins
for growth and repair.
Cell membrane
Nucleus
Nuclear membrane
Chromosomes
Smooth endoplasmic
reticulum
Mitochondria
Vacuoles
Rough endoplasmic
reticulum
Cytoplasm
c- Organelles: tiny structures in cytoplasm
perform special jobs.
that
Nucleus: “Control Center” Controls cell activities.
These are stored in the chromosomes found in
nucleus on genes.
Nuclear membrane: allows
and leave nucleus.
information to enter
Mitochondria: “Powerhouse” cell respiration
food is burned by combining it with oxygen to release
energy.
Endoplasmic reticulum: channels that run
throughout the cell store and transport materials.
Ribosome proteins used for growth and repair.
Vacuoles: stores materials.
4-Plant Cells differ from Animal Cells
a- Cell Wall: gives support and shape
b- Chlorophyll: contains chloroplast for carrying out
photosynthesis.
c- Large Vacuoles: stores mostly
water.
nucleus
ribosome
Rough
Endoplasmic
reticulum
cytoplasm
nuclear
membrane
mitochondria
chromosomes
Smooth Endoplasmic
reticulum
Vacuole
Chlorophyll
Cell membrane
Cell Wall
5- Bacteria cells have no nucleus, mitochondria, or
endoplasmic reticulum. They still carry out all five life
processes.
Cell Wall
Cell
membrane
Cytoplasm
Ribosomes
Microorganisms: Are unicellular organisms
1-Harmful Microorganisms: Cause
infectious diseases that can be passed on from one
organism to the next.
a. Noninfectious diseases: Diseases that are
not caused by microorganisms.
~High blood pressure, asthma, cancer etc..
~Causes = poor diet, allergies, chemicals,
heredity etc…
2-Helpful Microorganisms: about 5%
a. Examples:
~ Decomposers: Break down dead
materials and return nutrients back into
soil.
~ Yeast: bread, wine, and beer.
~ Mold: Cheese, and medicine
A- The Life Processes
Getting and Using Energy
•Getting ride of wastes
•Growth and Development
•Responding to Changes in Environment
•Reproduction
A Closer look at Life Processes:
1-Transport: is the movement of materials
through organism. Water is a key nutrient for
this to occur.
*Two types:
Diffusion molecules move from a high
concentration to a low concentration with out the
use of energy. Osmosis: diffusion of water.
Active Transport used by cells need to move
molecules from low concentration to a high
concentration. Cells require the use of energy.
2- Getting and using energy:
a- Nutrition plants: Green plants make own
food. Through the processes of photosynthesis
* Photosynthesis: plants use energy from the sun
and change carbon dioxide CO2 and water H2O into
sugar C6H12O6. Energy from the sun is therefore
stored in sugar.
*Photosynthesis produces oxygen O2.
*Chlorophyll green pigment in leaves
contains chloroplast needed for
photosynthesis.
b-Nutrition Animals: get energy “nutrition” by eating other
plants or animals. The original source of energy is the sun. “Water” is
also an important part of nutrition in plants and animals.
c- Respiration: is the processes that organisms use to release
“burn” energy stored in food. Respiration is the opposite of
Photosynthesis.
Photosynthesis: energy + carbon dioxide + water = sugar + oxygen
Respiration: sugar + oxygen = energy + carbon dioxide + water
All organisms get energy directly or
indirectly from the SUN
3- Getting ride of wastes : “Excretion”
process of removing waste from the body. Filtered out of blood.
water.
a-Wastes = Carbon dioxide, urea, salt &
excess
b-Wastes are removed by exhaling,
perspiring, and
urinating in animals, and
by transpiration in plants.
4-Responding to changes in the environment:
regulation Organisms
changes
respond to internal and external
in their environment known as Stimuli.
a- Examples = migration, drinking,
hibernation, growing of fur etc..
perspiring,
b- Regulation helps organisms maintain
“homeostasis” the maintenance of a
constant internal
environment.
5-Reproduction: Organisms reproduce
survival of species.
to ensure the
a- Two Types of reproduction:
1) Asexual Reproduction: process of
producing
a new organism with only
one parent. The new organism
has the
exact same DNA as the parent.
b- Types of Asexual Reproduction:
Fission or Binary Fission: one cell splits to form two cells with the
same DNA
Budding: a new organism grow from the body of the parent.
The bud can stay on to form a colony, or break apart
Regeneration: A new organism forms
from a
piece of the parent or the parent re-grows the missing piece
Sporulation: Some organisms
reproductive cells in a
Spore.
produce
protective covering called a
2) Sexual Reproduction involves the combination of DNA from two
parents. Fertilization is the joining of DNA from The male (SPERM,
POLLEN) and DNA of the female (EGG). The new organisms is a
combination of both parents.