The cell
Every living matter has six constituents: Carbon, Hydrogen. Oxygen, Nitrogen, Phosphorous, and Sulfur.
The most prominent element in things is carbon: Because
- It can form a wide range of stable covalent bonds
- Carbon-carbon chains are unlimited in length.
Organic compounds in the cell-like amino acids and nucleotides are monomers for nucleic acids and polysaccharides respectively.
Macromolecules – organelles – cells – tissues – organs – organ system – organism
Functions
- Protein is a polymer of amino acids – Structure and functionality of the cell
- DNA is a polymer of deoxynucleotides – stores genetic information
- RNA is a polymer of ribonucleotides – It transfers genetic information from DNA into the synthesis of proteins
- Polysaccharides are made of monosaccharides – example; glycogen is made up of glucose monomers which act as an energy storage molecule
- Lipid is a polymer of fatty acids and glycerol – stores long term energy for the cell during fasting or when glucose and glycogen is insufficient
The cell – basic unit of life
Two cell types
- Prokaryotes – Have a cell wall, no membrane-bound organelles, no central nucleus. Example; Bacteria
- Eukaryotes – Have no cell wall except plant cells, have a central nucleus, have membrane-bound organelles and are more complex than prokaryotic cells.
Cell Organelles
Nucleus
- Largest cellular organelle
- Two nuclear membranes and nuclear pore
- Genetic material (DNA)
- Nucleolus with ribosomal RNA and which controls cellular activities
Mitochondria
- The powerhouse of the cell
- Double membrane system
- Inner membrane folded to form cristae
- Circular stranded mitochondrial DNA
Endoplasmic reticulum
- Rough endoplasmic reticulum – Synthesis of proteins on embedded ribosomes
- Smooth endoplasmic reticulum – No ribosomes, synthesis of lipids and metabolism of drugs
Golgi apparatus
- Adds carbohydrates, lipids or sulfate metabolites to proteins
- Packaging and transport of proteins
- Formation of intracellular organelles
Lysosomes
- Acts as the digestive tract of the cell
- Involved in digesting cellular structures especially worn-out organelles
Produces different types of lysosomal enzymes called hydrolases which include:
- Lipases – for lipids
- Ribonucleotide – RNA
- Alpha-glucosidases
- Cathepsins – for proteins
Peroxisomes
- This organelle protects the cell from the toxicity of H2O2 (hydrogen peroxides). H2O2 = H20 + O2
- It also helps in oxidation of long-chain fatty acids (with carbon chains greater than 18).
- It is involved in the synthesis of glycolipids and plasmalogens
Disorders in peroxisomes:
They are commonly called peroxisome biogenesis disorders – This is characterized by a high concentration of long-chain fatty acids and low concentration of plasmalogens. An example of this disorder is the Zellweger syndrome which is characterized by a lack of peroxisomes.
Cytosol and Cytoskeleton
- The cytosol is the cellular matrix
- The cytosol contains metabolites, salts, and enzymes
The cytoplasmic filaments are categorized into three types:
- Microfilaments
- Actin filaments
- Intermediate filaments
The three are responsible for the structure, shape, and organization of the cell
Cellular functions
- Apoptosis – This is programmed cell death which is considered a natural death of cells
- It is highly regulated and occurs to prevent the cell from infections and replenish cells
Revision
lysosome
digestive ‘plant’ for proteins, fats, and carbs. Transports undigested material to cell membrane for removal. Cell breaks down if there is no lysosome.
vacuoles
membrane-bound, water and waste storage. (plants have large vacuoles.
chloroplast
found in plant cells, contains green chlorophyll, where photosynthesis takes place.
organelle
part of a cell that has a function
eukaryote
A cell with a membrane and organelles (like a plant or animal cell)
prokaryote
A single cell organism (like bacteria)
The diameter of most plant and animal cells is…?
10 to 50 um
Monomer
a simple compound whose molecules can join together to form polymers
Polymer
a naturally occurring or synthetic compound consisting of large molecules made up of a linked series of repeated simple monomers
3 main categories of lipids?
Triacylglycerols, phospholipids, and steriods
Whats the difference between a saturated fat and unsaturated fat molecule.
Saturated fats are all single bonds. Unsaturated have some double bonds.
Why don’t lipids dissolve in water
they are nonpolar
What bonds hold together cellulose and starch?
glycoside bonds
What bonds hold together proteins?
peptide bonds
What is the primary function of cellulose?
To keep plant walls strong
Why is cellulose so hard for animals to digest?
We can’t break the bonds that are horizontal, but we can the 45 degree angle ones.
What type of biomolecule is glucose?
monomer
what type of organisms make glucose
autotrophs, plants.
Why do we need glucose?
Itz the only thing the brain uses for energy.
Glucose bonds?
Glycoside bonds
Whats the function of ATP
to store energy within the cell
Where does our body get ATP
it is made in the mitochondria
How are enzymes related to proteins
All enzymes are proteins, but not all proteins are enzymes
Nucleic Acids, primary function?
make protein
Five monomers used to build all nucleic acids?
GCTA/U
