Download Characteristics of Living Things and Cell Structure and Function PPT

We all have these in common.
7 Characteristics of Life
Living things share 7 characteristics:
1. Living things are made up of units called
cells.
a. Every organism is composed of at least one
cell.
1.) single-celled or unicellular
2.) many-celled or multicellular
b. There are two broad categories of cells:
1) prokaryotic—no organized nucleus nor membrane
bound organelles; found in bacteria and cyanobacteria
2) eukaryotic—do have an organized nucleus and
membrane-bound organelles such as Golgi apparatus
and mitochondria. All other organisms such as plants
and animals have this kind of cell.
2. Living things reproduce.
There are two basic kinds of reproduction:
a) Asexual—only one parent and all offspring are
identical; for example, binary fission of bacteria or
amoebas.
b) Sexual—two cells from different parents unite to
produce the first cell of a new organism.
3. Living things grow and develop.
a) For single-celled organisms, growth is mostly
an increase in size.
b) Multicellular organisms go through a process
called development, where cells divide and
differentiate into different kinds of cells.
4. Living things obtain and use materials and energy.
a)All living organisms must be capable of releasing
energy stored in food molecules through a chemical
process known as cellular respiration..
b)Autotrophs (also called producers)—plants, most
algae, and some bacteria obtain their energy directly
from the sun through photosynthesis.
Cellular Respiration
• Respiration All living organisms need
energy. They get this by breaking down
nutrients, such as glucose, inside their cells.
This releases the energy from the nutrients.
We can describe respiration as: the
chemical reactions that break down
nutrient molecules in living cells to
release energy.
c) Heterotrophs (also called consumers)—most other
organisms, rely on the energy stored during
photosynthesis.
1. Herbivores—eat plants and other photosynthesizing
organisms
2. Carnivores—eat the herbivores or other carnivores
3. Omnivores—eat both plants and animals
4. Decomposers—such as bacteria and fungi; obtain
energy from the remains of organisms that have died
5. Living things respond to their
environment.
a) Organisms detect and respond to
stimuli from their environment.
b) A stimulus is a signal to which an
organism responds.
c) External stimuli include temperature
and light.
d) Internal stimuli come from within,
such as blood sugar level or feeling
thirsty.
e) An adaptation refers to the process of
becoming adjusted to an environment.
Adaptations may include structural,
physiological, or behavioral traits that
improve an organism's likelihood of
survival, and thus, reproduction.
6. Maintain homeostasis
• Homeostasis is the property of a system in
which variables are regulated so that
internal conditions remain stable and
relatively constant. Examples of
homeostasis include the regulation of
temperature
7. Living things are based on a universal genetic
code (DNA).
a) The directions for inheritance are found in
deoxyribonucleic acid or DNA.
b) The genetic code is basically the same for all
organisms on Earth.
1. Organism
2. Organ
System
3. Organ
4. Tissue
5. Cell
Cell Structure and Function
Notes
Discovery of the Cell:
•Mid 1600’s scientists began using
microscopes to observe living things
•Robert Hooke used microscope to
observe thin slice of cork—dead plant
material
Cork seemed to be made of boxlike chambers—Hooke called cells
•Anton van Leeuwenhoek discovered
living cells in pond water
Cell Theory:
•All living things composed of cells
•Cells are the basic unit of structure
and function in living things
•New cells are produced from
existing cells
Cell Parts and Their Functions:
Specialized cell parts called organelles—
“little organs”
1. Cell membrane—determines what goes
in and out of the cell
2. Cytoplasm—gel-like medium that holds the
organelles in position
3. Nucleus—control center of the cell
•
Double membrane that surrounds the nucleus—
nuclear membrane
•
Hereditary information inside the nucleus—
chromatin (DNA)
4. Ribosomes—makes proteins
5. Rough Endoplasmic Reticulum (rough ER)—
makes and transports proteins within the cell
•Called rough ER because of the ribosomes
found on its surface
6. Smooth Endoplasmic Reticulum
(smooth ER)—makes and transport
lipids and other materials within the cell
•
Called smooth ER because no ribosomes
found on its surface
7. Cytoskeleton—network of protein
filaments that helps cell maintain its
shape
8. Golgi apparatus—processes and
packages proteins and other substances
produced in the ER
9. Mitochondria—energy source of the cell
(powerhouse)
10. Vacuoles—sac-like structures for storage
•
Plant cells usually contain a large vacuole
that fills most of the cell—pressure from this
large vacuole helps plants support
themselves
Found in animal cells only:
11.Lysosomes—cleans up the cell and
digests unwanted materials
Found in plant cells only:
12.Cell wall—provides support and
protection for cell
•Composed mainly of cellulose (plant starch)—fiber for
our diet
13.Chloroplast—makes glucose using the energy
from the sun (photosynthesis)
Specialized Parts for movement:
1. Cilia (like little hairs)
2. Flagella (like a tail)
Specialized Cells:
Different cells in your body do different jobs. The
structure (how it’s built) of cells matches the
function (what it does).
• Plant Examples:
1.Leaf cell—contains many
chloroplasts to maximize
photosynthesis
2.Root cell (potato)—
contains many vacuoles to
maximize water and starch
storage
Which cell might contain many mitochondria
to produce more energy for movement?