Cell Biology Flashcards
What is the cell theory?
- Cells are the smallest independent units of life
- All living things are made up of cells
- Cells are formed by the reproduction of existing cells
Life on earth is what?
Carbon-based
What is an element?
A chemically pure substance that cannot be broken down
What are covalent bonds?
When electron pairs are shared, very strong
What is a valence shell?
The outer layer of the atom
What is electronegativity?
The attractive force that an atom exerts on electrons
How do ionic bonds form?
By chemical attraction of opposite charges
- The more electronegative atom steals an electron
What kind of bond does solid, water, liquid, and gas have?
Hydrogen bonds (sharing of an H atom)
Polar molecules are:
Hydrophilic (water-loving)
Non-polar molecules are:
Hydrophobic (water-hating)
What is hydrophilic interaction?
Attraction, polar to polar
What is hydrophobic interaction?
Attraction, non-polar to non-polar
What ions do acids release?
H+
What ions do bases release and accept?
Accepts H+ and releases OH-
What is carbon?
A “tinkertoy” atom
- Incredibly flexible- used to build many types of complex macro molecules
What is a common theme between living systems?
Many are biological polymers with repeated subunits
What is a polymer?
A repeating unit (more than two)
What are carbohydrates?
A source of energy
- Basic unit: CH2O
- Ex: glucose (disaccharides)
What are polysaccharides?
Form rigid biological structures (ex: cellulose + chitin)
What are the 3 classes of amino acids?
Electrically charged, polar, non-polar
What is the shape of a protein?
A folded polypeptide
What is the structure of a non-polar amino acid?
Amino acids have a hydrocarbon side-chain (ex: CH3)
What is the structure of a polar amino acid?
Amino acids have side chains with partial charge (polar uncharged), or net (+) charge, or net (-) charge
What are lipids?
Fats, steroids, phospholipids
What is fat?
Simple 3-carbon lipid
- Fatty acid tails, hydrophobic
What is a phospholipid?
2 fatty acid tails (hydrophobic) and charged phosphate head (hydrophilic)
What is a steroid?
Composed of carbon rings (5 or 6 carbons per ring)
- Cholesterol, estrogen, testosterone (hormones)
- Cell membranes (animals only)
What are the 4 bases of nucleic acids?
A (adenine), G (guanine) — Purines
T (thymine), C (cytosine) — Pyrimidines
What are the subunits of a nucleotide?
1 of 4 bases + a phosphate + a sugar
What is DNA?
A double helix (two strands linked together that are identical)
- bonded by hydrogen bonds
What is the structure of DNA?
- Anti-parallel strands of repeating subunits
- Backbone (phosphate and sugar) — covalent bonds
- Rungs: A/G ::: T/C (hydrogen bonds)
What does the 1st law of dynamics state?
That energy cannot be created or destroyed
What are the types of energy?
- Kinetic potential: mass, gravity, speed
- Chemical: e.g. chemical bonds, ATP
- Radiant: e.g. sunlight, photosynthesis
- Thermal e.g. sunlight, thermal regulation
What is energy transfer?
Described as work and heat
What is a calorie?
- Unit of energy represented on food labels
- Calories are consumed by cells to do work
- Extra calories can be stored as fat
What is the basal metabolic rate (BMR)?
Represents the resting energy of an awake, resting but alert person
- 70 Calories/hour or 1680 Calories/day
What is metabolism?
All chemical reactions occurring in the body
What is metabolic rate?
The rate at which the body uses energy
- Influenced by: body weight, sex, exercise, genetic makeup, age and nutritional status
What are enzymes?
Proteins that catalyze chemical reactions in the cell
•They work by lowering the activation energy needed for a reaction
•They lower the energy barrier required for a reaction
•They are very specific
•They speed up the rate of reaction (or product production) by reducing the energy needed for the reaction to occur
•Enzymes DO NOT create reactions that create reactions that would not occur in their absence
•If enzymes have more energy or are present, the energy barrier is lower
What is cellular respiration?
A series of chemical reactions that convert energy from food into chemical reactions that convert energy from food into chemical energy in ATP
What does ATP consist of?
Adenine, a sugar, and 3 phosphate groups
- it can power different kinds of work in the cell
What happens when a phosphate group is transferred from ATP to another molecule?
Energy is transferred and ADP is produced
What are prokaryotic cells?
- Generally small (1/10 the size of a small eukaryotic cell)
- No nucleus
- Few internal membranes
- Never multicellular, but can form colonies
- Cell wall made of peptidoglycan - sugars and peptides (ex: bacterial cell)
- Some are aerobic (use oxygen) or anaerobic (don’t use oxygen)
What are eukaryotic cells?
- Larger than bacteria
- Has a nucleus
- Many internal membranes
- Membrane-based organelles
- Unicellular or multicellular
- Cell walls- depends on kingdom
- All are aerobic (use oxygen)
What is the nucleus?
Contains cells’ DNA
What is the nucleolus?
more specialised part of the nucleus in the middle
What is the centriole?
involved in the development in spindle fibers (only in animal cells)
What are ribosomes?
Bind messenger RNA and transfer to synthesize polypeptides and proteins
What is the cytoskeleton?
Gives the cell structure
What is the plasma membrane?
separates interior of cell from outside of cell
What is the lysosome?
Contains degrading enzymes
What is the mitochondria?
The powerhouse of the cell
What is the rough endoplasmic reticulum?
Produces proteins
What is the Golgi apparatus?
involved in secretion and intracellular transport