Bioenergetics: the
study of energy flow and energy transformation among living systems.
What are some characteristics
of living organisms?
1.
2.
3.
4.
5.
6.
7.
8.
9.
Energy:
Free energy:
Heat energy:
Living cells need a constant
source of free energy for chemical work.
How do organisms obtain
energy and nutrients?
Heterotrophs:
Ex.
Autotrophs:
Ex.
Photoautotrophs:
Chemoautotrophs:
What is the relationship
between heterotrophs and autotrophs?
Organisms are linked because
of their need of energy and nutrients. Energy and nutrients flow from the
environment through the producers → consumers → decomposers
Producers:
Consumers:
Decomposers:
The abiotic (nonliving factors such as water and minerals) and
the biotic factors (living) make
up an ECOSYSTEM (ex. Forest, pond,
ocean). Within an ecosystem are
habitats where organisms live (ex. Bottom of the ocean). All ecosystems together comprise the BIOSPHERE.
Energy is the key to
maintaining organisms in all living systems.
1st Law of
Thermodynamics:
2nd Law of
Thermodynamics:
Cells need a way to break and form bonds in order to release energy and to perform work. Enzymes (catalysts) lower activation energy to make a reaction go.
Active site:
Substrate:
Metabolism: consists
of all the chemical activities and changes that take place in a cell or
organism.
2 types: synthesis
(anabolism) Òbuild up reactionsÓ
decomposition (catabolism) Òbreak downÓ
Anabolism: examples-
Catabolism: examples-
ATP: (adenosine triphosphate) a molecule that connects many energy conversion reactions during metabolism; Òenergy currencyÓ of living cells.
- energy is stored in the bonds of the molecule and can be transferred when bonds break and other form during a reaction
Why do we eat?
- food provides organisms with a source of raw materials
and energy (organic and inorganic compounds) required for growth and
maintenance. Heterotrophs need to
break down food (digestion) in order to absorb and then use the raw materials
and energy present in food.
Physical and Chemical
Digestion:
Ingestion: taking food
into the digestive tractÉ
Mouth → Pharynx →
Exophagus (1-10 sec)→ Stomach (3 hours) → Small intestine (3-6
hours) → Large intestine (11-16 hours) → Rectum (up to 48 hours)
Nutrients: needed for growth
and maintenance of the body.
Examples of nutrients:
Essential vs. Nonessential
nutrients
Kilocalories (kcal):
measurement of amount of energy released from a nutrient. (lipids: 9 kcal/g;
carbs and proteins: 4 kcal/g)