Also called subcellular structures, the parts that make up a cell like the nucleus, ribosomes, and mitochondria
Organelles
Each individual organelle has a specific role to play
Whencombined, multiple organelles will form a single cell
Cells
Come in all sorts of shapes and sizes and contain different combinations and numbers of organelles
Specialized cells
Different types of cells like epithelial cells, muscle cells, and glandular cells
Tissues
A group of similar cells that work together to carry out a particular function
Tissues
Epithelial tissue
Muscle tissue
Glandular tissue
Organs
A group of different tissues that work together to perform a particular function
Organs
Stomach
Pancreas
Liver
Organ systems
A group of organs that work together to perform a particular function
Organism
The highest level, with multiple organ systems working together
Other examples
Skin
Teeth
Lungs
Spleen
Bones
Testes
Immune system
Nervous system
Respiratory system
Endocrine system
Urinary system
Enzymes
Catalysts made by living organisms
Enzymes
They are large proteins made up of long chains of amino acids
They can fold into different shapes, each shape catalyzing a particular chemical reaction
How enzymes work
1. Enzyme has an active site with a unique shape
2. Substrate fits into active site
3. Enzyme speeds up the chemical reaction
Substrate
Reactant in a chemical reaction
Products
Smaller pieces that a substrate is broken into
Enzymes speed up chemical reactions without being consumed or changed in the process
Lock and key model
Original model where substrate had to fit perfectly into active site
Induced fit model
More realistic model where enzyme changes shape slightly to better fit the substrate
The active site of an enzyme is complementary to the substrate
The induced fit model is like putting your hand into a rubber glove - the glove molds to your hand
How temperature and pH affect the functioning of enzymes and the rate of enzyme controlled reactions
1. Increase in temperature increases rate of reaction
2. Rate starts to drop rapidly at high temperatures due to bonds breaking and active site changing shape
3. Enzyme becomes denatured at high temperatures
4. Optimal temperature is the temperature at which rate of reaction is highest
Denatured
Enzyme cannot bind to substrate and catalyze reaction anymore due to active site changing shape
Optimal temperature
Temperature at which rate of reaction is highest
How pH affects enzymes
1. If pH gets too high or too low, it will lower the rate of reaction
2. At first, active site just changes a bit so substrate can still fit but less well
3. Soon, active site changes shape so much that substrate can't fit at all and enzyme becomes denatured
Optimal pH
pH at which enzyme works best
Most enzymes in our body work best at neutral pHs of around 7
Enzymes that work in the stomach have an optimal pH of around 2 to function in the acidic environment
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Biological molecules/nutrients
Carbohydrates, lipids, proteins, vitamins, mineral ions, fiber, water
Foods normally have a mix of different nutrients, not just one
Carbohydrates
Found in starchy foods, fruits, vegetables; provide energy
Lipids
Fats and oils; provide energy, insulate, protect organs
Proteins
Found in nuts, seeds, meat, fish, legumes; building blocks for growth and repair
Vitamins
Organic molecules made by living organisms; needed in small amounts
Vitamin A
Found in liver, leafy vegetables; for vision, skin, hair
Vitamin D
Found in eggs, oily fish; helps absorb calcium
Minerals
Inorganic, simple molecules; needed in small amounts
Calcium
Found in dairy, leafy vegetables; for strong bones
Iron
Found in red meat, spinach, beans; component of hemoglobin