Biology Exam Review (Unit 2) Flashcards
What is metabolism?
The chemical reactions that occur in a cell or an organism
What is nutrition?
The process of providing the food necessary for health and growth
How are metabolism and nutrients related?
Metabolism is the process of turning nutrients into substances
What are biological molecules?
Biological molecules are complex chemicals. They are chemicals used in biological systems (living things)
Types of biological molecules
- Carbohydrates
- Proteins
- Lipids
Elements that make up carbohydrates
Carbon, hydrogen, and oxygen
Function of carbohydrates
- Used for energy
- Cellulose: used to maintain the shape of a plant and tolerate turgor pressure.
- Starch: energy store
- Glycogen: stores energy in the liver and muscles (found in animals)
Subunits or monomers of carbohydrates
Monosaccharides
Where are carbohydrates found?
Used in a cells and extensively in liver and muscle tissues
What is included in carbs?
Sugars, fibers, and starches
What are the main types of carbs
- Simple sugars (monosaccharides)
- Double sugars (disaccharides)
- Complex sugars (polysaccharides)
Elements that make up proteins
Carbon, hydrogen, oxygen, nitrogen, and sulfur
Function of proteins
Function in cell membranes, as enzymes, hormones, antibodies, and movement
Subunits or monomers of proteins
Amino acids
Structure of proteins
There are 20 amino acids in proteins and they have a strong bond which is known as peptide bond. The shape determines on the sequence of amino acids.
Elements that make up lipids
Carbon, hydrogen, and oxygen (makes molecules hydrophobic)
Function of lipids
- Used for energy
- Steroids: cell to cell communication
- Hormones
Where are lipids found?
In cell membranes, cholesterol, and in the nervous fat tissue
What are unsaturated fats?
Liquid at room temperature (oil)
What are saturated fats?
Solid at room temperature (butter)
Why are biological molecules so important?
They are useful chemicals that are needed by living organisms for metabolism
Carbohydrates include
- Sugars: Quickly converted into energy and are found in soda, cookies, juice, and treats.
- Fiber: Can’t be digested or used for energy and are found in beans, nuts, and seeds.
- Starches: Takes longer to convert into energy and are found on bread, pasta, vegetables, rice, and fruits
3 main types of sugars
- Simple sugars (monosaccharides): galactose, glucose, and fructose.
- Double sugars (disaccharides): lactose, sucrose (table sugar), and maltose.
- Complex sugars (polysaccharides): Whole grain foods and starchy vegetables.
Monosaccharides
Glucose: a simple sugar made in photosynthesis and used in respiration and transported in blood.
Disaccharides
Sucrose: a double sugar molecule made up of two molecules of simple sugars joined by a chemical bond.
Polysaccharides
Made by joining many simple sugar molecules together by chemical bonds. Glycogen, starch, and cellulose are examples of these complex sugars
Types of complex sugars
- Cellulose: found in cell walls of plant cells. It is used to maintain the shape of a plant because of its strength and it can tolerate turgor pressure.
- Starch: plant cells can change glucose into starch. Plants store starch as an energy store.
- Glycogen (animal starch): another complex carbohydrate made from glucose by animals as a store of energy in the liver and muscles.
Lipids: fat
It is made up of one molecule of glycerol attached to three fatty acids
Functions of fats
Fats are used for energy storage and thermal insulation in the body
Functions of steroids
Hormones/steroids are used for communication between the cells in the body and they are made of mostly carbon and hydrogen
How to test for starch - Lugol test
Use iodine solution to see if the extract has starch and the solution has a yellow/light brown color so if it turns into a blue-black color it is a positive result for starch but it remains the same if it does not have starch
Testing for reducing sugars
Use Benedict’s solution to see if the extract has reducing sugars and it is a bright blue color and it will change to red or orange if the extract has a positive result for sugars but if it does not contain reducing sugars it remains blue
Testing for proteins
Use Biruet solution to see if the extract contains proteins and the color is blue and if it has a positive result for protein it will turn purple, violet, or lilac but if it has no protein it will remain blue
Testing for fats
Use ethanol to check for fats and if it turns milky or cloudy that means it is a positive test for fat but it will remain the same if there is no fat
What is digestion?
The process of breaking down the foods we eat so that our body can get nutrients.
What is a small intestine?
They absorb most of the food and they are long but have a small diameter
What is a large intestine?
They produce and absorb vitamins and water and have a wide diameter that is large so it is tube shaped and connects to the small intestine and anus. The large intestine can also be called a colon.
Digestion process
- Mechanical = chewing (physical breaking)
- Chemical = enzymes that break food into molecules
What is a digestive tract?
The organs that food and liquids travel through after they are swallowed, broken down, absorbed, and they leave the body as waste.
What is diffusion?
Diffusion is the process of particles (atoms, molecules, ions etc.) moving from an area of high concentration to an area of low concentration. They diffuse DOWN the concentration gradient.
How does diffusion apply to the digestive system?
Nutrients are absorbed by the cells in the villi of the small intestine.
What is a solution?
A solution is made up of a solute (like salt) and a solvent (like water).
What is a solute?
A substance dissolving.
What is a solvent?
The liquid the solute dissolves.
What is a solution?
The solute dissolved in solvent.
What is osmosis?
Osmosis is the diffusion of water from a solution with a high concentration of water to a solution with a low concentration of water
Why do we feel thirsty after eating salty food?
The salt sucks the water out of our body.
What is a partially permeable membrane?
A membrane that only lets some substances pass and others not
What is a water potential gradient?
If the solute concentration of a solution increases, the potential for the water in that solution decreases.
3 types of solutions
- Hypotonic = less solute
- Isotonic = same
- Hypertonic = high solute
What is dynamic equilibrium?
Equal and constant movement from particles from one side to another
What is equilibrium?
The same amount of particles in all areas.
What is active transport?
Active transport takes molecules from a low concentration to a high concentration using energy (ATP). It is the opposite of diffusion.
Why does active transport need effort?
It needs more effort because they are going up the concentration gradient.
How is ATP produced?
Mitochondria (cellular respiration)
What is a dilute solution?
Dilute solutions have low concentration of solute.
What is a concentrated solution?
Concentrated solutions have a high concentration of solute.
