Unit 8: The vital functions (I)

Characteristics of the living things

• They’re 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.

BIOMOLECULESThey 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/FunctionGlucides orCarbohydrates

GlucoseCellulose

•To provide energy•To make structures

Lipids Fatty acidsCholesterol

•To provide energy•To make structures

Proteins HaemoglobinAntibodiesQueratine

•To transport oxygen•To fight microorganisms that cause disease•To make structures: hair, nails

Nucleic acid DNARNA

•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- Ramón 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 célula eucariota típica existen tres partes fundamentales: la membrana plasmática, una envoltura fina que rodea a la célula y permite la entrada y salida de sustancias y donde se pueden encontrar estructuras para el movimiento de la célula como cilios y flagelos; el citoplasma: gel donde flotan los orgánulos celulares de funciones diversas y específicas como las mitocondrias (orgánulo que da energía a la célula) y los ribosomas (orgánulo que sintetiza proteínas); y el núcleo: donde encontramos el material genético, los cromosomas.

1.2. Types of 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

Eukaryotic cells

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

Orgánulos celulares

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

Neuron

To store fat

To transmit information

Adipose

Nervous

See student’s 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 función de nutrición incluye varios procesos: la captación de nutrientes, su transformación, su distribución a todas las células y la eliminación de sustancias de desecho que se producen como resultado del uso que se hace de los nutrientes en las células. Esto es común a animales y vegetales. Para ello el cuerpo del ser vivo tiene órganos y aparatos especializados en la realización de estas tareas: aparato digestivo, respiratorio, circulatorio y excretor.

2.1. Autotrophic Nutrition

It’s 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 energía solar, que rompe los nutrientes y los recombina para formar materia orgánica, como la glucosa (un hidrato de carbono), y desprendiendo oxígeno.

CO2 + H2O + sales minerales + energía C6H12O6 + O23. Use of organic matter.

Organic matter is distributed to all cells.Las células la aprovechan para regenerar estructuras, crecer, y

realizan la respiración celular en sus mitocondrias, obteniendo así energía:C6H12O6 + O2 Energía + H2O + CO2

Bacteria cannot carry out cellular respiration, they get their energy by means of fermentation:

Fermentación láctica: Glucosa Ácido láctico + Energía

Fermentación alcohólica: Glucosa Etanol + Energía

4. Elimination of waste substancesIn 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).

Así, la materia orgánica producida en la fotosíntesis, pasa de unos seres vivos a otros en lo que se llaman cadenas tróficas.

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 gástrica (anémonas, corales, hidras o medusas) o bien con tubo digestivo (boca, estómago, intestinos y ano)

2. Gas Exchange.

En la respiración externa, se capta oxígeno y se elimina CO2

3. Transport

El aparato circulatorio lleva los nutrientes absorbidos en el tubo digestivo a todas las células, mediante la sangre (vertebrados) o hemolinfa (invertebrados).

4. Metabolism (use of the organic matter)

En las células los nutrientes se queman en las mitocondrias (respiración celular), obteniendo energía para fabricar moléculas orgánicas complejas, y produciendo desechos como CO2, amoniaco, urea, ácido úrico, etc.

5. Elimination of waste products

Dichas sustancias pasan a la sangre, que las conduce al aparato excretor.