CELLS & Organ Systems
Cells-the basic units of all living things
Cell Theory1.
All organisms are made of cells
2.
All cells come from existing cells
3.
Cells are the basic units of all living
things
Microscopes-Robert Hooke used a
microscope and was the first to see cells
Total magnification=
eyepiece magnification X objective
example: If the eyepiece=10X and
objective=40X, then
total magnification=10 x 40=400X
So, the object you are looking at appears
400 times larger
Cell Parts-
1.
Cell membrane-thin layer that holds
cell together
2.
Cell wall-protects and supports plant
cells only
3.
Nucleus-control center; DNA is here
4.
Mitochondria-powers the cell,
releases energy from food
5.
Ribosomes-makes proteins
6.
Lysosomes-break down food, digests
waste
7.
Golgi-packages materials
8.
Endoplasmic Reticulum (ER)-carries
materials around the cell
9.
Vacuole-mainly holds water and waste
10. Chloroplast-only in plant and algae
cells, absorb light to make food
Unicellular-one celled organism
Multicellular-an organism made up of more
than one cell
“I’m multicellular, ruff”
1. Similar cells combine to make tissue
2. Similar tissues combine to make an
organ
3. Organs that work together make an
organ system
4. Organ systems work together to make
an organism
Photosynthesis-process by which plant cells
capture light energy to make food
Carbon dioxide + water + lightoxygen +
sugar (glucose)
Chlorophyll-green pigment in plants that
absorb light
Most leaves are flat and wide so they can
absorb more light energy.
Respiration-In animals, cells use glucose for
energy
Oxygen + glucosewater + carbon
dioxide + energy
Photosynthesis can be thought of as the
opposite of respiration.
Cell membrane-selectively permeable
(allows some things to pass through it)
*Allows-water, oxygen, carbon dioxide
*Stops or limits-sugars and salts
No energy is needed for:
Diffusion-movement from higher to
lower concentration
Osmosis-diffusion of water
Active transport-movement through
membrane that requires energy, from low
to high concentration
Bacterial Cells-has cell wall & membrane,
but no nucleus
Some cause disease, but many are helpful
(digestion)
Virus
Bacteria
smaller
bigger
not a cell
unicellular
needs a host
host cells copy
all bad
host must fight
living on its own
asexual reproduction
good and bad
antibiotic treatment it off
Chromosome: in the nucleus, contains DNA
(determine traits)
Asexual Reproduction- one parent cell splits
to make 2 new cells (offspring);
offspring will have the exact same DNA as
the parent
Examples=
1. plants growing
2. skin, bone, blood cells
3. bacteria (fission)
4. starfish arm regeneration
For asexual, if a parent cell has 21
chromosomes, all offspring cells will have
21
Sexual Reproduction-requires 2 parents
Female sex cell=egg
male=sperm
Sperm fertilizes the egg
1.
The egg and sperm’s 23 chromosomes
combine to make a zygote, which has 46
(double)
2.
This gives offspring traits from each
parent
**What are the advantages of asexual
reproduction?
1.
No mate is needed, so more offspring
produced
2.
Faster
3.
Less chance for mutations (genetic
mistakes)
Disadvantage?
Since offspring is identical to parent, there
are no variations, they can’t adapt
**What is the advantage of sexual
reproduction?
Genes from 2 parents make adaptation
easier
Disadvantages ?
1.
A mate is needed
2.
Males can’t reproduce
Mutations are possible
Circulatory System
It transports:
1. Through red blood cells: Oxygen, CO₂,
Nutrients (glucose)
2. White Blood Cells fight disease
Main parts:
1. Heart-a two pump organ
-sends blood to lungs to get oxygen
-sends blood from lungs to body cells
that need oxygen
2. Blood Vessels
-Veins: Carry oxygenated blood to heart
from lungs to rest of body
-Arteries: Carry deoxygenated blood to
heart from rest of body to lungs
3. Capillaries-(smallest vessels!)Transport
oxygen, CO₂, and nutrients between
tissues and arteries and veins
Respiratory System
Inhales oxygen and exhales carbon dioxide
for cells to function
1. Trachea(windpipe)
2. Bronchi-2 tubes connecting trachea to
lungs
3. Alveoli-thin sacks in lungs where
diffusion of oxygen and CO₂ occurs
4. Diaphragm-main muscle under lungs to
pull and push air in and out
5. Lungs-main organ which sends
oxygenated blood to heart and gets CO₂
blood from heart
Muscular System-for body movement and
organ functions
3 Types:
1) Cardiac-involuntary, in the heart
2) Smooth-involuntary, all other organs
3) Skeletal-voluntary, attached to bones
Nervous System-transmits signals between
different parts of the body
2 Parts:
1) Central-brain, spinal cord, and retina
2) Peripheral-all others throughout body