The basics of CELS191 Flashcards by Georgia Rickerby

What are the characteristics of life?

Cellular organization
Reproduction
Metabolism
Homeostasis
Heredity
Response to stimuli
Growth and development
Adaptation through evolution

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What are the measurements used to measure cells and organelles?

Micrometres
1mm = 1000 micrometres
1 micrometres = 1000nm

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What are the measurements used to measure internal structures and organelles?

Nanometres (nm)

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How big are eukaryote and prokaryote cells?

Eukaryote (10 - 100 micrometres)

Prokaryote (less then 5 micrometres)

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How are mitochondria and chloroplasts?

mitochondria (1-10 micrometres)

chroloplasts (2-5 micrometres)

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How big are membranes and ribosomes?

Membranes (7-8 nm)

Ribosomes (25nm)

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What are the four things that are required for natural selection?

Variation - Individuals in a population vary from one another

Inheritance - Parents pass on their traits to their offspring genetically

Selection - Some variants reproduce more then others

Time - successful variations accumulate over many generations.

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What do phylogenetic trees show?

The evolutionary relationship amongst various biological species.

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What are the three domains of life?

Eukarya, Archea and Bacteria

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What are the building blocks of life?

Amino acids
Nucleobases
Simple carbohydrates
Lipids

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What are the macromolecules, and what are they made of?

Proteins (amino acids)
DNA and RNA (neucleobases)
Complex carbs (simple carbs)
lipids (lipids)

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What are the supramolecular assemblies?

membranes
ribosomes
chromatin

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What are organelles>

nucleus
mitochondria
golgi
ER

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What are polymeric molecules?

Polymeric molecules are molecules created by polymerisation of building blocks.

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What are the four levels of carbohydrates?

Monosaccharides (simple carbs aka sugars)
Disaccharides (simple carbs aka sugars)
Oligosaccharides (complex carbs)
Polysaccharides (complex carbs)

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What are monosaccharides? What are some examples?

The single building block of higher order carbohydrates

e.g. hexose, pentose

What are disaccharides? What are some examples?

Two monosaccharides joined together.
e.g. Glucose + fructose = Sucrose
Galactose + Glucose = Lactose
Glucose + Glucose = Maltose

What are oligosaccharides?

Several monosaccharides linked together. Approx. 10.

What are polysaccharides? What are some examples?

Many monosaccharides joined together (approx > 10 monosaccharides)
e.g. starch and cellulose (plant carbohydrate), glycogen (animal carbohydrate)

What are the functions of carbs?

Recognition
Energy e.g. starch and glycogen
Stucture e.g. cell wall

What are proteins? How do they differ from each other?

Molecules by which cells perform their functions in the whole organism e.g. gene makes proteins (the workhouse of the cell)
Proteins are polymers of amino acids
The 20 amino acids differ by there side chain group.

What are the functions of proteins?

Proteins perform a variety of biological functions e.g. structural, regulatory, transport, storage, catalytic, toxic etc..

What are lipids?

Lipids are not polymers, and are hydrophobic molecules.

They are heterogeneous.

What are the functions of lipids?

Structural e.g. cholesterol and phospholipids in the cell membrane
Regulatory e.g. testosterone, estrogen etc..
Energy e.g. Triacylglycerol (fat)

Why do cells need organelles?

They require many different processes that require different conditions, which need seperate compartments.

What are five things that organelles do?

- Provide special conditions for specific processes - Keep incompatible processes apart - Allow specific substances to be concentrated - Form concentrations gradients - Package substances for transport or export

What does a cell membrane do?

- A semi permeable barrier | - Controls movement of substances in and out of the cell

Why is there a cell size maximum limit?

The movement of substances in and out of the cell limits the size. A small cell has a greater surface area to volume ratio than a larger cell, which is needs to diffuse substances over the cell at a fast rate.

What are cellular membranes composed of?

A phospholipid bilayer

What is a phospholipid bilayer? What is it's structure?

Made of phospholipids that have a hydrophilic head and a hydrophobic tails. The head points to the outside and inside of the cell, while the tails point in to not come in contact with water.

What affects the fluidity of the membrane?

The composition of fatty acids. Unsaturated tails prevent packing, while saturated tails pack together nicely. Cholesterol is a lipid in the bilayer that stabilises membrane fluidity.

What is simple diffusion?

A form of passive transport which requires no energy. Membranes are permeable to lipid soluble (hydrophobic) molecules such as steroid hormones and gasses. - The particules move down the conc gradient and thus do not require energy. - Membrane restricts movement of water soluble and charged molecules. e.g. glucose, ions, water

What is facilitated diffusion?

Movement of hydrophilic molecules requires channels and carriers - Aids the movement of specific substances down the conc gradient - No energy required but some channels open and close in response to signals - Carriers undergo a shape change to help guide the molecule

What is active transport?

Requires transport proteins, which are carriers that use energy (supplied by ATP) - Moves specific substances against the conc gradient (up) - Allows the cell to have an internal conc of a substance that is difference from surroundings (may be higher in the cell then out of the cell)

What is co-transport?

Indirect active transport, one substance is pumped across the cell membrane and its conc gradient is used to power the movement of a second substance against its conc gradient.

What are the roles of membrane proteins?

- Transporters (Often specific to the cell type) - Signal transduction (relay messages from the body or environment into the cell) e. g. grow, divide, move, make something, die etc.. - Cell recognition (often involves glycoproteins) - Intercellular joining (some proteins form long lasting connections between cells) - Linking cytoskeleton and extracellular matrix (allows a cell to physically connect with protein structures outside the cell)