Lecture 1: Cell structure Flashcards
Types of cells
- There are two types of cells –> eukaryotic and procaryotic cells
-Eukaryotic cells –> Have
organelles.
-Procaryotic cells –> Don’t
have organelles
Single nerve cells
> Branching
Receives signals from up to 100,000 other nerve cells
Paramecium- a microorganism
> This protozoan is a single giant cell
Can swims by beating the cilia that cover its surface
Often lives in stagnant warm water
Can eat pathogenic fungi Cryptococcus neoformans
Chlamydomonas- a microorganism
> Can be found all over the world:
– Soil
– Fresh water
– Oceans
– Snow on top of
mountains
– Photosynthetic
– Swims with flagella
Saccharomyces cerevisiae
> Yeast cell
Used for baking bread
Reproduces by budding -–> Watch it under microscope for 20 minutes —> 1/2/4/8/16… cells
Helicobacter pylori
> Bacteria
Causes stomach ulcers
Uses a handful of whiplike flagella to propel itself though stomach lining
> While most strains are harmless, some, like the shiga toxin-producing E. coli (STEC)
In the United Kingdom, there were 516 deaths from invasive group A streptococcus (iGAS) during the 2022–2023 outbreak
Human epithelial cells
> Epithelial cells cover the inner and outer body cavities, such as the stomach and the urinary tract
Can exists in multiple layers for protection
Epithelia form the structure of the lung, including the alveoli or air sacs where gas exchange occurs
Cells line most organs, such as the stomach and small intestine, kidney, and pancreas. They also line the oesophagus
Cells are also found in ducts and glands, like the bile duct and salivary glands
Epithelia can specialize to act as sensory receptors. They form taste buds, line the nose, and are in the ear. They are also found in the eye.
Female reproductive organs are lined with ciliated epithelial cells
The skin is made of epithelial cells. Its striated layers demonstrate the extensive morphology of epithelia
Epithelia is the first type of cell to differentiate in the embryo. This occurs during the eight-cell stage.
Epithelial cell can change appearance depending on location
Human epithelial cell uses in forensics
> A person sheds about 400,000 skin cells per day
Can be recovered from clothes, weapon and other objects
DNA from these cells needs to be isolated and matched to a victim or suspect
Fingerprints
> Stratified layer of cells
Undulation of the ridges and furrows produce fingerprints, palm prints and sole prints
Chemical composition can change with aging
Proteins, lipids (fats/oils), water, inorganic ions
Epithelial cells
> Form protective barriers in tissues
May be specialized to absorb or secrete specific compounds
Muscle cells
> Responsible for movement of skeleton, heart, many internal organs (e.g., stomach)
Nerve cells
> Conduct electrical signals throughout the body
Control contraction of muscles
Responsible for the five senses (taste, touch, smell, sight, hearing)
Connective tissue cells
> Create extracellular material that holds cells together in tissue
May be specialized to absorb or resist external forces (e.g., tendons, vertebral discs, bones)
Plant cells
> Share most structures and functions with animal cells (common ancestor)
Can be highly specialized in different plant types (cactus vs. seaweed)
Prokaryotic cells
> Are single-celled organisms, each capable of performing all functions to live and reproduce
Lack internal membrane-bound compartments (organelles) but have complex structural organization
The most abundant types of molecules in cells
> Water
Carbon-based molecules:
-Lipids
- Carbohydrates (sugars)
- Amino acids
- Nucleotides
Osmosis
> Physiological saline (isotonic)= 0.9% (w/v) NaCl
Intravenous infusion, has to be sterile
Used since 1831
Lividity
> Lividity refers to the bluish-purple discoloration of skin after death.
It is a common sign associated with livor mortis, one of the four post-mortem signs of death, along with pallor mortis, algor mortis, and rigor mortis.
Livor mortis is characterized by lividity and occurs within hours after death.
Lividity occurs because the heart is no longer pumping blood throughout the body and, consequently, gravity pulls the blood down, resulting in the pooling of blood at the lowest point in the body
