Cell structure
CELLS AS THE BASIC UNITS OF LIFE
CELLS AS THE BASIC UNITS OF LIFE
Cell structure
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BIOLOGICAL TERMS
cell
cytoplasm
eukaryote
membrane
microscope
microscopic
nucleus
organism
prokaryote
What are cells?
• In this section you will often read the prefix cyto- as in cytoplasm, cytosol
or cytoskeleton. Cyto- means cell so if you read cytoskeleton it actually
says: cell-skeleton.
• All living organisms (plants, animals and micro-organisms) are made up of
cells.
• Cells are the smallest parts/building blocks of all living organisms.
• All living organisms can be put into two groups according to the
structures of their cells.
• The most important difference in structure is the presence of
a nucleus.
• Cells that contain a nucleus are classified as eukaryotic cells,
• while those without a nucleus are prokaryotic cells.
• We will specifically look at eukaryotic cells in plants and animals.
• Bacteria are the only organisms with prokaryotic cells.
• Plants and animals have eukaryotic cells.
• The study of cells is called cytology
• -cyto meaning 'cell'
• -logy meaning 'study'
• -logist refers to the person who does the studying.
• Cells are the basic structural and functional units of all living
organisms.
• Individual cells cannot be seen with the naked eye, because
they are too small.
• A microscope is an instrument used to see cells.
• Cells are microscopic because they can only be seen under a
microscope.
Robert Hooke (1635 - 1703).
• Robert Hooke was the first cytologist to identify cells under
his microscope in 1665.
• He decided to call the microscopic shapes that he saw in a
slice of cork "cells" because the shapes reminded him of the
cells (rooms) that the monks in the nearby monastery lived
in.
• Robert Hooke was the first to use the term 'cell' when he
studied thin slices of cork with a microscope.
Different types of cells
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BIOLOGICAL TERMS
carbon dioxide
DNA
hereditary
inherited
medium
oxygen
specialised
species
variation
• The human body is made up of many different kinds of cells.
• Different cells are specialised to perform a specific function.
• Depending on the function of the cell, it can be specialised
by having a different shape or size or may have some
components which other cells do not have.
EXAMPLES OF SPECIALISED HUMAN CELLS
Differences between specialised cells
• Tabulate One visible structural difference between the nerve and the blood cells.
• Also give ONE functional difference in the same table.
(5)
• Each specialised cell is adapted to perform its function.
• Adaptation: Having special features to perform a specific function.
• Even though there are many different types of cells, there are
components (parts) of the cell structure which are common
to all cells. There are also some structures which most, but
not all, cells have.
Cell Structure
BIOLOGICAL TERMS
• cell membrane
• cellular respiration
• mitochondria
• nuclear membrane
• nucleolus
• organelle
• protein
• selectively permeable
• vacuoles
MICROGRAPHS
Animal cell micrograph
Plant cell micrograph
• Micrographs are photographs taken through a microscope called a
transmission electron microscope.
• Schematic means a plan, outline or a model.
• Schematic diagram is a graphical representation of a plan or model
that is presented in a simple accessible way.
• Schematics use simple lines and symbols to communicate information
such as what, how and where.
SCHEMATIC DIAGRAM OF AN ANIMAL CELL
A – vacuole
B – Cell membrane
C – Nucleus
1: Nucleolus
2: Nuclear pore
3: Nuclear membrane
4: Nucleoplasm
5: Chromatin network
D- Cytoplasm
E - Mitochondrion