Universal Features Of Cells On Earth Flashcards
Describe the Plasma membrane
Made of lipid molecules with hydrophilic heads and hydrophobic tails arranged in a bilayer with proteins attached to the heads and to the proteins attached sometimes are sugar molecules
What do cells exchange with their surroundings ?
Sugars Amino acids Peptides Amines Ions Other
Who were the first organisms to communicate with each other ?How do cells communicate with other cells and within themselves ?
Bacteria .
Cells have extra cellular signalling molecules which bind to receptor proteins that sit in the plasma membrane of the target cell. They transmit that signal to intracellular signalling proteins which transmit the signal to the effector proteins .
Name some effector proteins and give examples of changes they cause
Metabolic enzyme - alters metabolism
Gene regulatory protein- alters gene expression
Cytoskeletal protein-alters the shape or movement of cell
How do all cells store their hereditary information ?
As DNA
How does DNA form a double stranded structure?
Why is it important that bases are complementary ?
DNA forms double stranded structure where complementary bases arrange themselves with each other A=T & C=G fundamental for when DNA splits along the axis to separate the two strands,during cell division and the fact that the bases are complementary is used to generate identical daughter molecules .
Name the stretch of DNA that encodes a protein
Gene
What are the 3 processes to make a protein?
- DNA synthesis(replication)-
- RNA synthesis(transcription)-
- protein synthesis(translation )
What is a codon ?
3 nucleotides in one RNA molecule that code for one amino acid
What is the genetic code?
The rules of the way the codons are translated into a specific amino acid
What a cells made from?
Water 70% Inorganic ions 1% Miscellaneous small metabolites 3% Proteins 18% RNA 1.1% DNA 0.25% Phospholipids & other lipids 5% polysaccharides 2%
Who said life is a “pattern in flux” and what did they mean?
Rudolf Schoenheimer(1942) Molecules in living cells in plants and animals are constantly being replaced/exchanged without us knowing and this is due to homeostasis
Define homeostasis
The ability or tendency of an organism or cell to maintain internal equilibrium by adjusting its physiological processes
Name one type of homeostatic mechanism
Negative feedback
Give a chemical example of homeostasis
Molecules in cells or blood
