Cell Biology Flashcards
How many types of essential oral cell types are there?
5
What are the names of the essential oral cell types?
Osteoblasts, Osteoclasts, Fibroblasts, Ameloblasts, Odontoblasts
What do living cells contain?
carbon + hydrogen, oxygen, nitrogen, macromolecules, small organic molecules, solutes and solvent
What type of small organic molecules do living cells contain?
sugars & amino acids
What type of solutes do living cells contain?
dissolved salts, ions
What are macromolecules?
Carbohydrates, Proteins, Lipids, Nucleic Acids
What are sugars?
Simple carbohydrates
What are examples of simple carbohydrates?
glucose, fructose, galactose & mannose
What is a polysaccharides?
Polymerised sugars into larger molecules
What are examples of polysaccharides?
glycogen, starch, cellulose
What is glycogen?
Large branched polymers of glucose and are main energy storage molecules of animals
What are proteins?
Polymers of amino acids
What are two main types of proteins?
Enzymes (functional), Structural ( cell support)
What are functions of proteins?
Acts as a catalyst, regulates proteins or genes, source of transportation, anti-bodies
What is Haemoglobin?
An oxygen binding protein
How many common amino acids are there?
20, 9 are essential
Why are amino acids polymerised?
To make short polymers (peptides) or long polymers (proteins)
What can amino acid side chains consist of?
Charged, uncharged, polar (hydrophilic) , non-polar (hydrophobic) chains
What is a peptide bond?
It is formed by amino acids which one of the aminos in the group has undergone a reaction with a COOH of another amino acid.
What is an enzyme?
A macromolecule that act as chemical catalysts (protein)
Why are enzymes chemical catalysts?
They promote or accelerate specific chemical reactions from energy in the form of ATP or by the substrate
What does ATP stand for?
Adenosine triphosphate
What is ATP?
It is the common currency of cells
Where is energy stored in ATP?
in the high-energy bonds linking the phosphate molecules
What are lipids made up of?
They are composed of Oxygen, Carbon and Hydrogen and are mainly water insoluble
What do lipids consist of?
Fats, phospholipids, steroids
How much energy does the fat store in lipids?
2 x energy yield compared to carbohydrates
What is a phospholipid?
molecules with a hydrophilic phosphate head group and a hydrophobic lipid tail
Why are phospholipids important?
They are a major component of biological membranes
What are steroids?
A large group of lipids that act as structural components or hormones that possess a steroid nucleus with side chains
What are two important nucleic acids?
Ribonucleic Acid (RNA), Deoxyribonucleic Acid (DNA)
What is RNA and DNA?
They are polymers of subunit molecules called nucleotides
What are nucleotides made of?
They are composed of a 5-carbon sugar attached to a nitrogen base
What are purines?
Adenine (A) or Guanine (G)
What are Pyrimidines?
Cytosine (C) or Thymine (T)
How is DNA made?
By nucleic acids that are polymerised into a double stranded helical molecule called the double helix
What is the Central Dogma?
The flow of sequential information from gene to protein and never backwards
What are the two exceptions to the central dogma?
Reverse transcription and prions
What is reverse transcription?
It is a DNA polymerase enzyme that transcribes single-stranded DNA into RNA.
What is an example of reverse transcription?
HIV
What are prions?
A defective protein converting a normal protein into a defective form
What are examples of prions?
BSE or ‘Mad Cow Disease’
How can stem cells differentiate into other cells e.g liver cells, lung cells, nerve cells etc
A mosaic system and a highly coordinated pattern of expression due to very complex interplay between genetic programming and the environment
What is the cytoplasmic membrane?
a fluid mosaic model which comprises of a phospholipid bilayer with interspersed proteins
What is the cytoplasmic membrane function?
To separate cytoplasm from the surrounding environment and maintains integrity of the cell and controls the entry and exit of molecules in and out of the cell
What is the function of the membrane protein?
controls the movement of molecules across the membrane, interacts with extracellular molecules, and binds to the neighbouring cells, provides recognition system, and enzyme functions.
What are cytoplasms?
A water-based gel-like substance containing many different proteins and other molecules suspended in cytosol
What does a cytoplasm contain?
A variety of specialised functional structures called organelles
What are the two types of things organelles can be?
membranous and non-membranous
What is a membranous organelle?
it can possess its own plasma membrane and can be surrounded by single or double membranes
What is a non-membranous organelle
It is not surrounded by any membranes.
What is an endoplasmic reticulum?
To produce proteins for the rest of the cell to function.
What are the two types of endoplasmic reticulum?
Smooth ER and rough ER
What is the function of the smooth ER?
Smooth endoplasmic reticulum lacks ribosomes and helps synthesise and concentrate various substances needed by the cell such as lipids
What is the function of rough ER?
it has ribosomes which are small, round organelles whose function it is to make those proteins. Sometimes, when those proteins are made improperly, the proteins stay within the endoplasmic reticulum.
What are ribosomes?
An intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell.
What is a ribosome made of?
RNA and protein
What is the Golgi apparatus?
A membranous organelle composed of stacked cisternae
Where is the golgi apparatus located?
near the nucleus
What is the function of mitochondria?
To produce ATP by oxidative phosphorylation
What is a mitochondria?
A membranous organelle consisting of two mebranes
What is the difference between a saturated fat and a unsaturated fat?
A unsaturated fat contains an alkene and a carboxyl whereas saturated fat only contains a carboxyl group
What is a proteasome?
A hallow proteinaceous non-membranous
What is the function of a proteasome?
Destroys unwanted proteins such as ubiquitns
What is a peroxisome?
A small membranous vesicle
What does a peroxisome contain?
Enzyme catalase and peroxidase
What is the nucleus?
It is generally the largest in the cell and is surrounded by a double membrane.
What does the nucleus contain?
the entire genome
What is the function of the nucleus?
Selectively generates messenger RNA according to cell’s requirements and is the function centre of DNA.
What is the nucleolus?
A prominent structure inside the nucleus composed mostly of RNA
What is the nucleolus function?
Synthesises ribosomal RNA
What are cell connections?
Cells that must be attached to each other or to an extracellular matrix
How are cell connections formed?
By membrane proteins
What are types of membrane proteins that form cell connections?
intergins, selectins, cadherins and immunogloblins
What are three types of cell-to-cell connections?
Desmosomes, gap junctions and tight junctions
What is a desmosome?
A intercellular junction that mediate cell-to-cell adhesion which can be shaped like spot welds or a belt-like arrangement
What is a gap junction?
It joins the cytoplasm of adjacent cells and allows communication, transport or electrical signals between cells
What are tight junctions and where are they located?
six-pack-like collar around apical regions and impermeable seal around groups of epithelial cells
