Title: The Processes of the Cell
1The Processes of the Cell
2What has to happen to your cells in order to grow
from a baby into an adult?
3How do we know our cells are working?
- What do you think your cells must do in order to
stay alive?
4Your cells are constantly working to perform many
activities such as getting food, removing wastes,
growing, reproducing, and making new materials
5Your cells work to keep all of these activities
in balance, which is known as homeostasis.
6If your cells do not have the materials necessary
to conduct their activities, they send out
various signals to let the rest of your body know.
7Homeostasis is also important because if your
cells are not balanced, chemical reactions can
not occur. This means that your cells can not
perform their job correctly.
8How are our cells able to do all of these
activities when they are surrounded by a barrier,
the cell membrane?
9In our previous unit, we learned that the job of
the cell membrane is to allow materials in and
out of the cell.
10The cell membrane is semi-permeable. This means
that it can let some materials pass through while
others can not.
11Since we now know that materials can and must
move in and out of a cell in order for it to
survive, lets discuss the different ways in
which this occurs.
12Some small particles can easily move in and out
of a cell, this happens through diffusion.
- Diffusion is when particles move from an area
where it is crowded (high concentration) to an
area where it is less crowded (low concentration)
13Examples of Diffusion
- Smell of food, perfume, air freshener, and other
substances
14Diffusionhttp//www.bbc.co.uk/scotland/education
/bitesize/standard/biology/investigating_cells/cel
ls_and_diffusion_rev3.shtml
15Osmosis is the diffusion of water. Water moving
from where it is crowded to where it is less
crowded.
16Examples of Osmosis
- Cooking rice, beans, and macaroni
- Watering a plant
17Pure water diffuses more than any other water
mixture because it is more crowded (has a higher
concentration) than any other water mixtures.
18In this picture a red blood cell is put in a
glass of distilled water (pure water with no salt
or sugar in it).Â
Because there is a higher concentration of water
outside the cell, water enters the cell by
OSMOSIS. The cell bursts and dies
19Osmosishttp//www.bbc.co.uk/scotland/education/b
itesize/standard/biology/investigating_cells/cells
_and_diffusion_rev4.shtml
20If your cell needs a particle and the particle is
too big to diffuse into the cell membrane, does
your cell just go without that particle?
21Although some particles are too large to diffuse
into or out of a cell, they can still get in or
out of the cell membrane.How?
22If a particle is too large to naturally go
through a cell membrane, it can enter or exit in
two ways
- Particles can move in and out of a cell through
protein doorways - If a particle is still too large to fit through a
protein doorway, it can be engulfed (eaten) by
the cell
23Protein Doorways
24Engulfing
25Particles that have to go through protein
doorways can enter one of two waysPassive
transport -particles can enter easily through the
protein doorwayActive transport -particles
require energy to move through the protein doorway
26(No Transcript)
27Active transport is different from passive
transport because it requires energy. Active
transport is necessary to make particles move
against their natural tendency. In active
transport, particles move from less crowded (low
concentration) to more crowded (high
concentration).
28Active Transport
29Active transport is important in organs such as
the kidneys when harmful particles are made to
stay in the organ when they naturally want to
diffuse
30If a particle is too large to fit through a
protein doorway, then it can enter the cell by
being engulfed, endocytosis, or it can be
released from the cell by exocytosis
31Endocytosis and Exocytosis
32Endocytosisand Exocytosis
33Do cells need energy?
34Cells need energy to carry out the activities
which allow them to live, grow, and reproduce
35Cells get energy from food. Plant cells make
their own food while animal cells must get their
food by eating other things.
36Plant cells make their own food through the
process of photosynthesis. In this process,
plant cells take in light energy and change it
into a food called glucose.
37PhotosynthesisSunlight Water Carbon Dioxide
C6H12O6 (Glucose) and Oxygen
38Photosynthesis
39Once food is obtained or made in animal cells and
plant cells, it must be broken down to release
energy. This process is called cellular
respiration.
40Cellular RespirationC6H12O6 (Glucose) Oxygen
Carbon Dioxide, Water, and Energy (ATP)
41Cellular Respiration
42Photosynthesis and Cellular Respiration are the
opposite of one another
43We have discussed all of the ways in which cells
live and grow by getting the nutrients they need,
but living organisms would not exist over long
periods of time if cells did not reproduce.
44Living organisms can reproduce sexually and/or
asexually.
45Sexual reproduction requires two parents to make
an offspring that has characteristics of both
parents
46Organisms that reproduce sexually
47Asexual reproduction requires one parent to
produce an identical offspring
48Organisms that reproduce asexually
49Bacteria reproduces asexually through a process
called binary fission
50Cells reproduce by making more cells or dividing
through a process called mitosis (one cell makes
two)This is a form of asexual reproduction.
51Cells make sex cells to help in the reproduction
of multi-cellular organisms through a process
called meiosis (one makes four)
52MeiosisThis is a form of sexual reproduction
53Meiosis