This document provides an overview of cell structure and organization. It defines prokaryotic and eukaryotic cells, and describes the main components of animal and plant cells, including the cell membrane, nucleus, cytoplasm, organelles, mitochondria, chloroplasts, and cell wall. Specific organelles like the endoplasmic reticulum, Golgi body, ribosomes, lysosomes, centrioles, and vacuoles are explained. Videos are provided for virtual tours of typical animal and plant cells. Activities at the end instruct students to fill in organelle names and compare animal and plant cells.

1. Unit 1. Organization of the Human Body
3rd year ESO
UNIT1. THE CELL
CELLS The structural and functional units of all living things.
PROKARYOTIC CELLS Cells with no nucleus or nuclear membrane.
EUKARYOTIC CELLS Cells which have a nucleus separated from the cytoplasm by the
nuclear membrane.
CELL MEMBRANE It is the outer covering of a cell. It regulates the substances exchange
between the inside and the outside of the cell.
NUCLEUS It contains the genetic material of the cell (DNA).
NUCLEOLI (sing. NUCLEOLUS) Round body in the nucleus that produces the parts of the
ribosomes.
CYTOPLASM It is the inside of the cell. It is a fluid where many of the chemical reactions of
the cell take place. It contains the nucleus, the organelles, mitochondria, vacuoles, etc.
CYTOSKELETON It is a "skeleton" contained within the cytoplasm. It maintains cell shape,
transports substances from one place to another in the cytoplasm and enables cellular
motion. It is made up of different kinds of filaments.
ORGANELLES Small structures in the cytoplasm responsible for cell functions.
TRANSPORT SYSTEM/ENDOPLASMIC RETICULUM Internal network of membranes.
There are two types:
 ROUGH ER This is where proteins formed in the ribosomes are stored and processed.
 SMOOTH ER This is where lipids are formed.
GOLGI BODY/GOLGI APPARATUS/GOLGI COMPLEX Set of membranous sacs which
collects, modifies and distributes the substances made by the ER.
RIBOSOMES Organelles where proteins are made. They can be isolated and dispersed in
the cytoplasm or stuck to the rough ER and the nuclear membrane.
MITOCHONDRION It is the part of a cell where energy is obtained through the process of
respiration.
LISOSOMES Round sacs in animal cells containing enzymes to digest substances. They
don´t exist in plant cells.
CENTRIOLES Two bodies in animal cells which are vital to cell division. They don´t exist in
plant cells.
CELL WALL Thick, rigid part of plant cells that surrounds the plasmatic membrane and
provides support and protection. It is made of cellulose.
VACUOLES They are like bags, surrounded by membranes, where storage or waste
substances accumulate, mainly water. They are also in animal cells, but they are smaller.
CHLOROPLASTS Organelles that store a green pigment called chlorophyll and where
photosynthesis takes place.
AMYLOPLAST They store starch.

2. Unit 1. Organization of the Human Body
3rd year ESO
ANIMAL CELL
PLANT CELL
Videos:
Tour on an animal cell: http://www.youtube.com/watch?v=PXbv95P3uhI
Tour in a plant cell: http://www.youtube.com/watch?v=LMVQ-INMSVw

3. Unit 1. Organization of the Human Body
3rd year ESO
Activities.
1. Complete the names of the organelles.
2. Explain the differences between an animal cell and a plant cell.