Unit 8: The vital functions
(I)
Characteristics of the living
things
Theyre formed by the same molecules
(biomolecules)
All cells come from other cells.
They carry out 3 vital functions:
Nutrition function.
Interaction function.
Reproduction function.
ELEMENTS THAT FORM LIFE:BIOELEMENTS AND
BIOMOLECULES.
BIOELEMENTS
They are chemical elements.
All the living organisms are formed by the same chemical elements.
The Earth is made of about 100 chemical elements.
Life is made of, in a 96% ,4 of them: oxygen, carbon, hydrogen and nitrogen.
Oxygen is the main element.
Carbon is the most representative.
BIOMOLECULES
They are the combinations of the bioelements to form molecules. There are 2 types:
INORGANIC MOLECULES, they can exist outside and inside living organisms.
They are WATER AND MINERAL SALTS.
MINERAL SALTS appear in the minerals and rocks. They make up
different structures likes bones, shells and teeth. They are present in internal fluids,
like tears,sweat and blood.
WATER is the most abundant substance in living things. Living things
obtain water directly by drinking it, or indirectly from substances tnat contain
water.Plants obtain water from the environment.
ORGANIC MOLECULES, they appear in the living matter.
They are sugars or glucides, lipids, proteins and nucleic acid
Biomolecules
Example
Use/Function
Glucides or
Carbohydrates
Glucose
Cellulose
To provide energy
To make structures
Lipids
Fatty acids
Cholesterol
To provide energy
To make structures
Proteins
Haemoglobin
Antibodies
Queratine
To transport oxygen
To fight microorganisms
that cause disease
To make structures: hair,
nails
Nucleic acid
DNA
RNA
To control cell function
and heredity
The female Praying Mantis eats male after carrying out the
copulation. The three vital functions are mixed.
1. The cell, basic unit of the
living organisms.
The cell is the unit of organization and
functioning of the living organisms.
-
1665- Robert Hooke- He observed the first cell structures in cork.
1831- Robert Brown- He observed the cell nucleus.
1838- Schleiden
- He realized that all plants are formed by cells.
1838- Schwan- He realized that all animals are formed by cells.
1855- Virchow
- New cells can only be formed from other cells.
1906- Ramn y Cajal- The nerve tissue is also formed by cells.
1.1. The cell, a unit of organizaton
Living things:
- UNICELLULAR (single-celled) (bacteria, some fungi, some
algae , protozoa)
- MULTICELLULAR (animals, plants, some fungi,some algae)
Basic structure of a cell:
Plasmatic membrane
Cytoplasm
Nucleus
En la clula eucariota tpica existen tres partes
fundamentales: la membrana plasmtica, una envoltura
fina que rodea a la clula y permite la entrada y salida
de sustancias y donde se pueden encontrar estructuras
para el movimiento de la clula como cilios y flagelos; el
citoplasma: gel donde flotan los orgnulos celulares de
funciones diversas y especficas como las mitocondrias
(orgnulo que da energa a la clula) y los ribosomas
(orgnulo que sintetiza protenas); y el ncleo: donde
encontramos el material gentico, los cromosomas.
1.2. Types of cells
Eukaryotic cells
There are 2 basic types of cells:
1.Prokaryotic cells. They have no nucleus. They have no nuclear membrane.
They are sympler than eukaryotic cells. Bacteria are made up of prokaryotic cells.
2.Eukaryotic cells have a nucleus, separated from the cytoplasm by the nuclear
membrane. Algae, protozoa, fungi, animals and plants have eukaryotic cells.
Prokaryotic cells
(bacteria)
Eukaryotic cell
Orgnulos celulares
Diagram of a typical animal (eukaryotic) cell.
(1) nucleolus,(2) nucleus,(3) ribosome,(4) vesicle
(5) rough endoplasmic reticulum (ER),(6) Golgi apparatus,(7)Cytoskeleton,
(8) smooth endoplasmic reticulum,(9) mitochondria,(10) vacuole,(11)
cytoplasm,(12) lysosome,(13) centrioles within centrosome
Plant cell
Both animals and plants
have eukaryotic cells,
but there are some
differences.
Plant cells have a rigid
cell wall which surround
the plasmatic
membrane.
Plant cells are usually
polyhedral, but animal
cells are various shapes:
round, square
Plant cells have
organelles called
chloroplasts which are
responsible for
photosynthesis.
Cells in multicellular living things are organised to carry out different functions:
Cell
Function
Tissue
Red Blood Cell
To carry oxygen
Blood
Adipocite
To store fat
Adipose
Neuron
To transmit
information
Nervous
See students book, page 133
2. Vital functions: Nutrition
Nutrition refers to all the processes which enable living things to obtain the
energy and matter they need to live.
The cells take in substances, called nutrients, from the outside. Nutrients
are obtained from food, which is rich in biomolecules: carbohydrates,
lipids, proteins, water, mineral salts
La funcin de nutricin incluye varios procesos: la captacin de nutrientes, su
transformacin, su distribucin a todas las clulas y la eliminacin de
sustancias de desecho que se producen como resultado del uso que se hace de
los nutrientes en las clulas. Esto es comn a animales y vegetales. Para ello el
cuerpo del ser vivo tiene rganos y aparatos especializados en la realizacin de
estas tareas: aparato digestivo, respiratorio, circulatorio y excretor.
2.1. Autotrophic Nutrition
Its carried out by plants, algae and some bacteria.
It has several steps:
1.Intake of nutrients from the environment.
Plants take water (by the root) and mineral salts (by the leaves)
Las algas y las bacterias toman los nutrientes directamente del
medio.
2. Production of organic matter.
This process is called photosynthesis.
La clorofila de los cloroplastos capta la energa solar, que rompe los
nutrientes y los recombina para formar materia orgnica, como la glucosa (un
hidrato de carbono), y desprendiendo oxgeno.
CO2 + H2O + sales minerales + energa
C6H12O6 + O2
3. Use of organic matter.
Organic matter is distributed to all cells.
Las clulas la aprovechan para regenerar estructuras, crecer, y
realizan la respiracin celular en sus mitocondrias, obteniendo as energa:
C6H12O6 + O2
Energa + H2O + CO2
Bacteria cannot carry out cellular respiration, they get their energy by means of
fermentation:
Fermentacin lctica: Glucosa
Fermentacin alcohlica: Glucosa
cido lctico + Energa
Etanol + Energa
4. Elimination of waste substances
In cellular respiration waste substances are eliminated (CO2) and in
fermentations, and ethanol
Importance of Photosynthesis
Plants produce oxygen.
They purify the air because they use carbon dioxide.
Photosynthetic organisms (producers) make the food that the rest ol
living things consume (consumers)
- Primary consumers(hervibores)
- Secondary consumers (carnivores).
As, la materia orgnica producida en la fotosntesis, pasa de unos seres vivos a otros
en lo que se llaman cadenas trficas.
2.2. Heterotrophic nutrition
Living things which feed on organic matter produced by other living things.
They transform this matter to obtain nutrients and energy.
1. Absorption of organic matter from the environment.
Los organismos unicelulares capturan los alimentos y los digieren en una
vacuola.
Animals have a digestive system to turn food into simple molecules.
(bien con cavidad gstrica (anmonas, corales, hidras o medusas) o bien con tubo digestivo
(boca, estmago, intestinos y ano)
2. Gas Exchange.
En la respiracin externa, se capta oxgeno y se elimina CO2
3. Transport
El aparato circulatorio lleva los nutrientes absorbidos en el tubo digestivo a todas
las clulas, mediante la sangre (vertebrados) o hemolinfa (invertebrados).
4. Metabolism (use of the organic matter)
En las clulas los nutrientes se queman en las mitocondrias (respiracin celular),
obteniendo energa para fabricar molculas orgnicas complejas, y produciendo
desechos como CO2, amoniaco, urea, cido rico, etc.
5. Elimination of waste products
Dichas sustancias pasan a la sangre, que las conduce al aparato excretor.
