Download How Do Cells Work?

How Do Cells Work?
A Cell is a System that Works in a System

A system is made up of a group of parts that
interact to perform a function
Group of parts:
organization of different elements or subsystems that accomplish a function
Interactions:
relations and communications between the
parts
Function:
the product, action or consequence of the
interactions
Examples of Systems
System
Group of
parts
Interaction
Function
iPod
Body, electronics,
battery,
earphones
Store and
organize data,
energize, produce
sound
Play music,
videos...
Screw driver
Shaped tip, shaft,
handle
Transfer rotation
Turn a screw
Cardiovascular
Heart, arteries,
capillaries, veins.
Pump, regulate,
distribution
Transport the
blood
Education
School Boards,
Schools,
Educators
Transfer
knowledge and
culture
Socialize
PLANT CELLS
1. Cell Wall
(parts)
8. Vacuoles
2. Plasma
Membrane
3.
Cytoplasm
4. Nucleus
DNA
7. Mitochondria
6.
Chloroplast
5. Endoplasmic
Reticulum
ANIMAL CELLS
(parts)
1. Plasma Membrane
DNA
2.
Cytoplasm
3.
Nucleus
6.
Vacuoles
5.
Mitochondria
4. Endoplasmic Reticulum
For Your Entertainment…
Cells need nutrients

Nutrients: The particles from which cells
are nourished. They are derived from
digested food
Inputs and Outputs

Inputs: Inputs are substances that enter the cell
and are necessary to its activities

Main Inputs: Water, nutrients and oxygen

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The cell’s mitochondria release the energy from
the nutrients when the nutrients come in contact
with oxygen.
These nutrients are used as material for
construction (to grow) or repair (to heal) the
organism.
Inputs and Outputs


Outputs: Wastes or useless substances
that must leave the cell
Main outputs: Water, carbon dioxide, and
waste from cellular functions
The Cell and its Environment


The cell membrane is like the border
between two countries.
At a border crossing agents verify the
items people transport. Items like
firearms, food and plants are usually
forbidden. Customs posts help in this
verification.



The cell membrane verifies materials
entering the cell or exiting it.
Like a customs post, a cell membrane lets
certain substances to enter or exit, but
forbids passage to others.
Because the membrane only lets certain
substances pass we call this type of
membrane selectively permeable.
Diffusion



To enter a cell membrane a substance
must move.
Diffusion is the movement of particles
when they shift from a region where they
are more concentrated to a region
where they are less concentrated.
Substances enter and exit the cell by
diffusion.
Osmosis



Water is the most abundant substance
both inside and outside the cell.
Approximately 70% of a cell is water.
In the cell, the water contains various
dissolved particles: nutrients, carbon
dioxide, waste.
Water particles are very small: they can
enter and exit the cell easily.


Water particles move from areas with low
amounts of dissolved substances into
areas of higher amounts.
The passage of water across a membrane
that only allows certain substances to pass
is called osmosis.
http://www.stjohn.ac.th
/Department/school/bio
_pix/osmosis.gif
Vital Functions of the Cell


Energy contained in the food is released
during a chemical reaction called cellular
respiration.
Plants produce their food themselves with
a function called photosynthesis.
Photosynthesis




Plants use sunlight as a source of energy
Sunlight in plant cells manufactures sugars
called carbohydrates from water and carbon
dioxide.
The water comes from the roots, which draws it
from the soil.
The leaves absorb carbon dioxide present in the
air.
Photosynthesis
Inputs
Outputs
Carbon Dioxide
Water
Solar Energy
Oxygen
Chemical reaction
occurring in the
plant cell
(chloroplasts)
Carbohydrates
Cellular Respiration




In living things, cellular respiration is necessary.
It transforms carbohydrates into energy.
This transformation takes place in the
mitochondria.
The mitochondria absorbs carbohydrates and
oxygen and then a chemical reaction causes the
oxygen to release the energy present in the
carbohydrates.
This energy can then be used by the cells
Cellular Respiration
Inputs
Outputs
Oxygen
Carbon Dioxide
Chemical reaction
occurring in the
animal or plant cell
(mitochondria)
Water
Carbohydrates
Energy