Chapter 10 - Digestion
Define the following terms in detail:
AUTOTROPHS
An autotroph is an organism that is
capable of producing its own food.
It does not rely on ingesting other
organisms. Instead, autotrophs are
often photosynthetic.
e.g. plants, algae, photosynthesizing
bacteria
Define the following terms in detail:
HETEROTROPHS – organisms that
must ingest other organisms to
obtain required nutrients. These
organisms lack organelles required
to photosynthesize or otherwise
create all required nutrients.
Define the following terms in detail
ESSENTIAL NUTRIENTS
Essential nutrients are nutrients that
must be obtained through the diet.
These are nutrients that are
required for proper cellular
functioning.
Define the following terms in detail
DIGESTIVE SYSTEM
All of the organs involved in
processing food in order to break it
down, absorb required nutrients,
and eliminate waste products
produced as a result.
Define the following terms in detail
INTRACELLULAR DIGESTION
The process of breaking down larger
nutrient molecules within a cell. This
process may involve using organelles
such as the lysosome, or it may occur
when macromolecules are broken down
by HYDROLYSIS.
This process is used by amoeba and
paramecium, using phago and
pinocytosis.
INTRACELLULAR DIGESTION
Define the following terms in detail
EXTRACELLULAR DIGESTION
The process of breaking down food
outside of the cell, and absorbing
only the required nutrients.
Bacteria, fungi, and most animals
use this method.
EXTRACELLULAR DIGESTION
Cells excrete digestive enzymes
onto food material. The enzymes
work outside of the cell, and break
down larger molecules into one that
can be taken in across a cell
membrane easily. Only nutrients
needed by cells are absorbed, and
wastes remain outside the cell.
EXTRACELLULAR DIGESTION
CELL
FOOD
1.
Enzymes
are
secreted
from the
cell
2.
4.Nutrient
s enter
the cell
from food
3.
Required
nutrients
are
released
Food
is broken
down by
enzymes
Define the following terms in detail
PERISTALSIS
Involuntary muscle movements that
causes food to move through the
digestive system. This forces food
to move in a one-way direction
(usually) through all digestive
organs, and past those that secrete
important enzymes and juices for
digestion
PERISTALSIS
Peristalsis is the result of smooth
muscle contractions in the hollow
organs of the digestive tract
(esophagus, stomach, intestines).
It will force food material to move
even against gravity (you can drink
while standing on you head).
PERISTALSIS
2. How is a one-opening digestive
system different from a 2-opening
digestive system?
ONE-OPENING SYSTEM
In organisms with a one-opening
system, the “mouth” serves to allow
food material into the organism,
and it also releases wastes.
Examples of organisms with one
opening systems are hydra.
ONE-OPENING DIGESTIVE SYSTEM
ONE-OPENING SYSTEM
Food is taken into a central body
cavity where extracellular
digestion breaks down the food
material. Required nutrients are
absorbed into surrounding cells, and
waste products are pushed back out
through the mouth.
TWO-OPENING DIGESTIVE SYSTEM
In organisms with a 2-opening
system, a mouth is used to take
food into the body. The food
passes through a tube (digestive
tract) where it is processed and
nutrients are absorbed. Wastes are
excreted through a second opening
called the anus.
TWO-OPENING SYSTEM
TWO-OPENING SYSTEM
What is digestion?
DIGESTION is the process by which
food materials are broken down into
smaller enough pieces that they
may be absorbed into the cells of an
organism.
There are 2 types of digestion:
physical digestion and
chemical digestion.
What is the difference between
ingestion, digestion and egestion?
These are the three processes
involved in bringing food into the
body (ingestion), processing it to
obtain required nutrients
(digestion) and eliminating wastes
from the body (egestion).
What is the difference between
physical (mechanical) digestion and
chemical digestion?
PHYSICAL DIGESTION
This is the act of mechanically breaking
down food into smaller pieces. This
process is accomplished by chewing
food, which physically breaks large food
particles down into small enough pieces
to be swallowed), and through the action
of the stomach.
PHYSICAL DIGESTION
Action of the stomach
The lining of the stomach (the rugae)
provides a rough, muscular surface.
When the rugae rub together, they grind
solid food particles into smaller and
smaller bits. Eventually, with the addition
of water and digestive chemicals, the
solid food is converted into a liquid called
chyme.
Rugae of stomach
CHEMICAL DIGESTION
Chemical digestion involves adding
digestive enzymes and juices to
food in order to break the chemical
bonds that hold larger food
molecules together, to create
particles that are small enough to
move across cell membranes.
CHEMICAL DIGESTION
Chemical digestion begins in the
mouth (salivary amylase), continues
in the stomach (gastric juice), and
into the small intestine (intestinal
enzymes, bile, pancreatic juice).