Biology and Geology

ESO 3

YEAR 2014-15

unit 1: Cells and tissues

HUMANS AS MULTICELLULAR ORGANISM

A CELL

It is the smallest unit of a living thing capable

of performing the three vital functions:

- nutrition

- interaction

- reproduction

There are two types of living things

Unicellular organism(colonies)

Multicellular organism

Levels of organisation

Cells

Tissues

Organs

Systems

The organism

Levels of organization in humans

TYPES OF CELLS

Clasify the type of cell by looking where the

genetic material is:

Prokaryotic cells

Eukaryotic cells (Animal and Plant Cells)

Prokaryotic cells

Prokaryotic Cells

In prokaryotic cells the DNA floats in the

cytoplasm. This cell type is characteristic of

bacteria.

It has plasmatic membrane, cytoplasm and

DNA (it is the substance that contains the

genetic information for the characteristics of

the cell and how it functions).

Prokaryotic cells

They measure between 1 and 10 micrometer

in length.

We find plasmids (small fragments of DNA),

ribosomes, mesosomes (folds in the cell

membrane), a rigid outer cover called cell

wall and some species have flagella or

fimbria.

Eukaryotic cell

The DNA of eukaryotik cells is found inside

an organelle called the nucleus.

Eukaryotic cell (animal)

Organelles of eukaryotic cells (animal)

Cell membrane

Cytoplasm

Nucleus

Mitochondria

Ribosomes

Endoplasmic reticulum (rough and smooth)

Golgy body

Organelles of eukaryotic cells (animal)

Vesicles

Lysosomes

Cytoeskeleton

Centrioles

Sometimes flagela or cilia.

Cheek cell

Eukaryotic cell (plants)

Onion Cell

Organelles of eukaryotic cells (plants)

Cell wall

Cell membrane

Cytoplasm

Nucleus

Mitochondria

Ribosomes

Endoplasmic reticulum (rough and smooth)

Golgy body

Organelles of eukaryotic cells (plants)

Vesicles

Lysosomes

Cytoeskeleton

Vacuole

Choroplast

Type of nutrition in cells

Autotrophic cells; They produces their own

food. They produce organic nutrients from

inorganic substances.

Heterotrophic cells; They obtain organic

nutrients by feeding on other living things or

their derivates.

HUMAN CELLS

Humans cells nutrition is heterotrophic. They

are eukariotic cells which means that they

have a cell membrane, cytoplasm and

nucleus.

Cells vary a great deal in their size and

shape depending on their function.

Types of human cells

The cell membrane

It is a very thing elastic layer that cover the

cell.

Function: it controls which substances go in

and out, detects stimuli from the

environement and enables cells to

communicate with each other.

The cell or plasmatic membrane

The cytoplasm

It is a gel-like subtstance which fill the cell. It

contains the organelles.

Function: a lo of chemical reactions take

place in the cytoplasm.

The nucleus

The nucleus

The DNA is organised in the nucleus. The

DNA is joined to proteins to make it stronger

and more compact. This association is called

chromatin.

The nucleus is surrounded by a porous

double membrane and contains a substance

similar to cytoplasm (nucleoplasm) and the

nucleolus where ribosomes are formed.

The cytoskeleton

It is a network of filaments that gives shape

to the cell and enables it to move.

Mitochondria

Mitochondria

Function: Cellular respiration. Energy is

obtained in a process where food is burnt

using up oxigen and carbon dioxide is

released.

Ribosomes

They make cell proteins.

Golgi body

It processes and packages substances. The

vesicles transport the substances to other

parts of the cell or to the outside of the cell.

Endoplasmic reticulum

It transports proteins made by the ribosomes

and them to the Golgi body.

Lysosomes and others vesicles

Lysosomes carry out cellular digestion,

converting substances into other subtances

which are useful in the cell.

Vesicles: they store or transport substances

made by the Golgi body.

Centrioles

They have two main functions:

- to control the movement of the

chromosomes during the mitosis and

meiosis.

- to take part in the formation of the cilia and

flagella.

Organelles found in plant cells

Big vacuoles

Chloroplasts

Cell wall

Big Vacuoles

The sap inside the vacuole exerts pressure

on the inside of the cell, which is very

important because it maintains the plant

cell´s rigidity.

Chloroplasts

They perform photosynthesis.

Cell wall

It protects and gives rigidity to the cells.

Human tissues

The tissue is an aggregate of cells that have

a similar structure and function.

Organs

An organ is a grouping of tissues to carry out

a certain function. For example: the heart,

the stomach or the brain.

Major organ systems

They are groups of organs which cooperate

to perform a common activity. For instance:

the digestive system or the respiratory

system.