Life at cellular level Flashcards
Describe the structures present in all cell types
- Cytoplasm
- Ribosome
- Cell (plasma) membrane
Define role of nucleus.
- Contains DNA
- In a nuclear membrane
- Nucleoli are sites of ribosomal RNA synthesis and ribosomal assembly
- Closely associated with RER
Define role of endoplasmic reticulum and Golgi apparatus
- Has RER, SER
- RER has ribosomes,
- Ribosomes synthesise proteins
- RER modifies proteins
- SER produces lipids, steroid hormones and metabolises toxins
- Golgi apparatus packages proteins in preparation for transport outside cell
Define role of mitochondria
- matrix contains majority of enzymes required for metabolising food molecules
- inner membrane has cristae (folds) for larger surface area.
- outer membrane contains pores
Define role of lysosomes and peroxisomes
- vesicles that contain enzymes
- Lysosomal enzymes are degradative and digest biological materials
- Peroxisomal enzymes degrade long chain fatty acids and other foreign toxic materials
- reactions generate hydrogen peroxide and peroxisomes break down hydrogen peroxide
Define role of cytoskeleton
- maintain cell shape
- maintains internal cell order
- Helps with intracellular transport
- Drives and guides cellular migration
- Protein fibres of cytoskeleton connect with extracellular space and helps with assembly of tissues
Define role of flagellum and cilium
- projections supported by cytoskeleton
- Cilia are short, many present, move with stiff power stroke and flexible recovery strokes
- Flagella are longer, with one or two present and have snakelike movement
Describe structure and function of the eukaryotic cell membrane
- double layer of lipids with phosphate groups attached
- selectively permeable bilayer
- embedded with proteins such as receptors to detect signalling molecules
Define stem cells
Stem cells can differentiate into many (multipotent) or any (pluripotent) cell types
Describe cell differentiation
Differences in gene expression and local cellular environment can cause daughter cells to develop into different cell types
What is apoptosis.
Controlled and programmed cell death
normal process and essential for normal function
What is necrosis
death of cells in response to injury or infection
not a normal process
What are the major elements used to construct human biomolecules.
Hydrogen, Oxygen, Nitrogen, Carbon
State the importance of chemical functional groups
Groups of elements that attach to carbon structures and give specific chemical properties to molecule
State the importance of molecular configuration in determining bimolecular function
- fixed arrangement of atoms in a molecule
- biomolecules contain carbon double bond and have rigid structure
- only 2 distinct configurations, cis and trans
What is the importance of conformation in bimolecular function.
spatial arrangement of groups
groups can have different positions in space due to rotation of single bonds.
What are the 5 chemical reactions occurring in living organisms, with examples.
- Redox reactions
- Making/breaking bonds
- Internal rearrangement
- Groups transfer
- Condensation and Hydrolysis
Describe the general structure of proteins
long chains of amino acids formed by condensation reactions
carboxyl and amino group joined by peptide bond
Describe the general structure of nucleic acid
- polymers of nucleotide monomers
- linked by 3,5-phosphodiesterase bonds
What are Pyrimidines
Cytosine - C
Thymine (DNA) - T
Uracil (RNA) - U
What are Purines
Adenine - A
Guanine - G
Describe the general structure of lipids
repeating units of fatty acids
What are the different types of fatty acids
- Saturated - single bonds
- Mono-unsaturated - one double bond
- Poly-unsaturated - more than one double bond
What is the function of fatty acids in the cell membrane
fatty acid tail of phospholipids is hydrophobic and allows them to be used for drug delivery
