Week 2: Building Blocks Flashcards
What happens in autocatalytic reactions?
Simple building blocks come together to give a complex product.
The product then aggregates to give primitive cell-like structures or “protocells” such as micelles or vesicles.
The protocells speed up reactions in time and give rise to more complex behaviour.
What is Darwin’s theory of evolution?
Processes by which genetic mutation that enhance reproduction become more common in successive generations of a population.
What are the two classes of cells?
Prokaryotic (bacteria)
Eukaryotic
What is the difference between the two classes of cells?
Prokaryotic cells lack a nuclear envelope, whereas eukaryotic cells have their nuclear material separated from the cytoplasm.
What indicates the evolutionary relationship between the two types of cell?
Prokaryotic cells are smaller and simpler, but they share the same molecular mechanisms governing their lives as eukaryotic cells, indicating their evolutionary relationship.
What are the major differences between the structure of prokaryotic and eukaryotic cells?
Prokaryotes don’t have a nucleus and rarely have membrane bound organelles.
What are the similarities between the structure of prokaryotic and eukaryotic cells?
Both have DNA as genetic material, have exterior membranes, have ribosomes, accomplish similar functions and are very diverse.
Sketch a basic eukaryote.
(11)
Sketch a basic prokaryote.
(12)
What shape are most bacterial cells?
Spherical, rod-like, or spiral.
What is the range of diameters of most bacterial cells?
1-10 um
What is the structure of E. coli?
Rod-shaped, about 1um in diameter and 2um long.
It is surrounded by a rigid wall composed of polysaccharides and peptides.
Within the cell wall is the plasma membrane composed of a phospholipid bilayer and associated proteins.
The DNA is a singular circular molecule in the nucleoid and is not surrounded by a membrane separating it from the cytoplasm.
What components are eukaryotic cells made up of?
Nucleus
Ribosomes
Mitochondria
Chloroplasts
Lysosomes
What happens in the nucleus of a eukaryotic cell?
Where DNA replication and RNA synthesis occurs.
What happens in the ribosomes of a eukaryotic cell?
Where the translation of RNA into proteins takes place.
What happens in the mitochondria of a eukaryotic cell?
They plat a role in energy metabolism. They are the site for oxidative reaction and are responsible for generating most ATP derived from the breakdown of organic molecules.
What happens in the chloroplasts of a eukaryotic cell?
The sites of photosynthesis and are found only in plant cells and green algae.
What happens in the lysosomes of a eukaryotic cell?
Provide specialised metabolic compartments for digestion of macromolecules and oxidative reactions.
Give examples of eukaryotic cells.
Protist
Plant cell
Budding yeast cell
Red blood cell
Fibroblast cell
Nerve cell
Retinal rod cell
What surrounds the nucleus?
The nucleus is membrane bound and is surrounded by a double membrane.
How does DNA vary in different parts of the body?
DNA is similar in every cell in the body. However, depending on the specific cell type, some genes may be turned on or off.
What is the prominent structure in the nucleus and what is its role?
The nucleolus.
Produces ribosomes, which move out of the nucleus to positions on the rough endoplasmic reticulum where they undertake protein synthesis.
What is the role of the mitochondria?
Provides the energy to a cell to move, divide, produce secretory products and contract.
How are mitochondria structured?
Are membrane-bound with a double membrane.
The outer membrane is fairly smooth but the inner membrane is highly convoluted forming folds called cristae.
What happens on the cristae of the mitochondria?
Sugar is combined with oxygen to produce ATP, the primary energy source for the cell.
What does endoplasmic reticulum do?
Functions in both the processing and transport of proteins and the synthesis of lipids.
What happens at the Golgi apparatus?
The proteins are further processed and sorted for transport to their final destinations.
Carbohydrates are synthesised here and it is also the site of lipid synthesis.
What is the cytoskeleton?
Is a network of protein filaments extending throughout the cytoplasm.
It determines the structural framework, the cell shape and is responsible for movement of entire cells.
What are the five main types of tissues?
Epithelial cells
Connective tissues
Blood
Nervous tissue
Muscle cells
What do epithelial cells do?
Form sheets covering body surface and line the internal organs.
What are the connective tissues?
Bones and cartilage.
What are the blood tissues?
Contains red blood cells for oxygen transport, inflammatory reactions and immune response.
What do nervous tissues consist of?
Nerve cells (neurons) and sensory cells (ear, eye).
What are muscle cells responsible for?
Production of force and movement.
What processes can be studied by looking at prokaryotic cells?
Molecular genetics
DNA replication
Genetic code
Gene expression
Protein synthesis
Why are prokaryotic cells suitable to look at fundamental processes?
Small genome size
Rapid growth (20-40 min cycle)
Simple nutritional requirements
What are the three essential components in a living cell?
Nucleus
Ribosomes
Mitochondria
What is the biological function of the nucleus?
Where DNA replication and RNA synthesis occur.
What is the biological function of ribosomes?
Where the translation of RNA into proteins take place.
What is the biological function of the mitochondria?
Is the site to undertake energy metabolism and provide with the energy. They are also the site for oxidative reactions and are responsible for generating most ATPs derived from the breakdown of organic molecules.
How do cells construct their subcellular compartments?
In eukaryotic cells, each subcellular compartment is surrounded by membrane lipids.
Within each compartment, molecules of different sizes and nature are uniquely organised; packed in unique morphological structures from micron to nano scale.
These hierarchical organisations are often termed self-assembly or co-assembly, driven by inter and intra-molecular interactions such as van der Waals, electrostatic and H-bonding.
Briefly describe the key structural features of a membrane lipid.
Carry 2 hydrophobic acyl chains and one zwitterionic, polar or charged heads.
Hydrophobic»_space; hydrophilic so are spreadable on the surface of water but not soluble.
Packed into a membrane bilayer quickly through self assembly so that the hydrophobic chains are packed away from direct water exposure.
Explain the difference between prokaryotic and eukaryotic cells.
Prokaryotic cells are much simpler in terms of subcellular compartments and more importantly, their nucleus is not covered by a membrane.
Describe the structural differences between cell types.
Bacterial cells, such as E. coli, have a very rigid cell wall and they look mostly rod-like, thus with a distinct size and shape.
Mammalian cells do not have a rigid membrane or cell wall, they are very soft, looking similar to a cracked egg.
Describe the difference in growth conditions between cell types.
Growth conditions are very different, requiring different growth media, nutrition or energy.
For example, plant cells can grow on sugar and lights, whilst mammalian cells rely on sugar, protein and inorganic nutrients.
