Cells And Tissues Flashcards
What are cells
The cell is the basic unit of all organisms
Has a highly organised structure which enables it to carry out its vital functions
Key scientist of cell theory
Robert Hooke
Theodore Schwann
Matthias Schleiden
Rudolf Virchow
Three principles of cell theory
All living things are made up of one or more cells
Cells are the most basic unit of structure and function in all living things
All cells are created by pre-existing cells
Prokaryotic cells
Bacteria and Archaea.
Amongst the simplest of organisms and made of single cells (unicellular).
Cell membrane, cytoplasm, no membrane-bound organelles, and DNA is free-floating in cytoplasm.
Cell division by binary fission.
Most are 0.2-2.0 μm.
Eukaryotic cells
Animal, Plant, Protist and Fungal.
More complex cells, made of many cells (multicellular).
Cell membrane, cytoplasm, cell organelles, and DNA within a nucleus.
Cell division by mitosis.
Most are 5-100 μm.
Structure of organelles
Nucleus
Mitochondria
Ribosomes
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Golgi apparatus, and Golgi vesicles
Centrioles
Lysosomes
Organism
An individual plant, animal or single-celled lifeforms
Organelles
Specialised structures within the cell that have specific functions
Cytoplasm
The fluid component of the cell, enclosed by the cell membrane and surrounding
the organelles
Membrane
All membranes consist of a phospholipid bilayer together with proteins and other
components. They are selectively permeable and can control movement of substances across
the membrane as well as being the sites of many important processes in the cell
Phospholipid
Large molecule formed from a glycerol molecule covalently bound to two fatty
acid molecules and a phosphate group
Phospholipid bilayer
: A double layer of phospholipids with the hydrophobic tails arranged
towards the middle and the hydrophilic head group on the outside. Forms the basis of all biological membranes
Hydrophlilic
Can interact with Water
Hydrophobic
Repels water
Erythrocytes
(red blood cells) carry oxygen around the body, by using haemoglobin. The cells lack a nuclei and most other organelles so it has more room for haemoglobin. They are flattened and biconcave in shape, which increases the surface area of the cell, allowing more efficient diffusion of oxygen. The elastic plasma membrane allows the cell to change shape and squeeze through narrow capillaries
Neurones
nerve cells are highly specialised to enable them to conduct electrical impulses in the nervous system. The impulse occurs in one direction, with sensory neurones in the peripheral nervous system (PNS) conducting impulses towards the central nervous system (CNS), and motor neurones conducting impulses away from the CNS
Squamous Epithelial Cells
most important feature is that they are flattened cells, supported by a basement membrane, which makes up the epithelium. They are well suited to exchange surfaces, such as in the lungs. The basement membrane is a thin layer of protein fibres and polysaccharides which help support the epithelium (it is not a phospholipid bilayer like cell membranes)
Erythrocytes
Carry oxygen haemoglobin it lacks a nuclei they are flattened and bisonaux this increases its surface area it can also change shape which allows it to squeeze through narrow capillaries
Neurones
Sensory neurones- peripheral nervous system (PNS)
Central nervous system (CNS)
Motor neurones
Squamous epithelial cells
Flattened cues supported by a basement membrane - the basement is a thin layer of protein fibres