exam 1 study guide Flashcards
What is the definition of biology?
Biology is the scientific study of life and living organisms
What are the major characteristics of life?
built of cells, grow and develop, reproduce, respond to stimuli, homeostasis, metabolism, evolution
what is the definition of a cell?
A cell is the basic structural and functional unit of all living organisms. It is the smallest unit that can carry out all the processes necessary for life.
what is metabolism?
the sum of all chemical reactions that occur within a living organism to maintain life.
what is catabolic reaction?
These reactions break down larger molecules into smaller ones, releasing energy in the process. For example, cellular respiration breaks down glucose into carbon dioxide and water, releasing energy.
What is anabolic reactions?
These reactions build larger molecules from smaller ones, requiring an input of energy. For example, photosynthesis builds glucose from carbon dioxide and water.
What did we predict would happen to carbon dioxide levels when dead and alive meal worms
were tested with CO2 sensors? What were the results of our experiment? In what units is
carbon dioxide measured? Be sure to be able to calculate results if I asked per meal worm, per
minute, per hours, etc
The prediction might be that alive mealworms will produce more carbon dioxide compared to dead ones due to their metabolic activity. The results should show higher CO2 levels from live mealworms. CO2 levels are measured in parts per million (ppm) or as a concentration in millimoles per liter (mmol/L
Are viruses alive?
Viruses are not considered alive by most biologists because they do not exhibit all characteristics of life, such as cellular organization or metabolism. They require a host cell to reproduce and cannot carry out metabolic processes independently.
what is science?
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. It involves observing, experimenting, and analyzing phenomena.
What are the four steps of the scientific method?
Observation
Hypothesis Formation
Experimentation
Analysis and Conclusion
What is a hypothesis?
A testable prediction about the relationship between variables.
What is a control?
A standard for comparison in an experiment.
What is meant by accepting or rejecting a hypothesis?
Based on experimental results, a hypothesis may be supported (accepted) or refuted (rejected).
What is a theory?
A well-substantiated explanation of some aspect of the natural world, based on a body of evidence and repeatedly tested.
What is the difference in the use of the word theory in science compared to general use of the term?
Often used to mean a guess or hypothesis without substantial evidence.
What is pH?
pH is a measure of the hydrogen ion concentration in a solution, indicating its acidity or basicity
What is the range of pH?
The pH scale ranges from 0 to 14, where 7 is neutral, below 7 is acidic, and above 7 is basic.
What do acid solutions contain?
Contain higher concentrations of hydrogen ions (H+)
What do basic solutions contain?
Contain higher concentrations of hydroxide ions (OH-)
What general pH are most drinks?
Many beverages have a pH between 2 and 7. For example, soda is acidic (pH 2-4), while some mineral waters are neutral or slightly basic.
Why do plants tend to make alkaline (basic) compounds?
Plants may produce alkaline compounds to neutralize acidic soil conditions or to balance nutrient availability
What is a solution
A homogeneous mixture of solute and solvent (e.g., saline solution)
What is a solvent
The substance doing the dissolving (e.g., water).
What is a solute
The substance being dissolved (e.g., salt).
What is the cell theory?
- Lowest level of structure capable to perform all chemical reactions necessary to sustain life
- Arise from previously existing cells: mitosis
Who was one of the first scientists to observe cells?
Robert Hooke
What type of
cells did he observe?
cork cells
Why was the theory not proposed until the 1800’s?
The cell theory was formally proposed in the 19th century as microscopes improved and more evidence accumulated.
What is a light microscope?
Resolution limit:
~0.2μm (small bacterium)
Effective magnification limit:
~1000X size of specimen
Functional limitations: cannot resolve subcellular anatomical structures called organelles.
Can see: mitochondria, most bacteria, nucleus, most plant and animal cells
What are organelles: any of a number of organized or specialized structures within a living cell.
What is a transmission electron microscope (TEM)?
e- beam focused through thin section of specimen
Allows for study of internal ultrastructure of cells.
What is a scanning
electron microscope (SEM)?
e- beam is bounced off surface
Give topographical information about a specimen’s surface area
What type of images do SEM scopes yields?
producing three-dimensional images
What type of images do TEM scopes yield?
Produces high-resolution, two-dimensional images.
What type of images do light microscopes yield?
n practical terms, bacteria and mitochondria, which are about 500 nm (0.5 μm) wide, are generally the smallest objects whose shape can be clearly discerned in the light microscope; details smaller than this are obscured by effects resulting from the wave nature of light.
difference between magnification and resolving power
Magnification enlarges the image, while resolving power distinguishes between two close objects.
calculate amplification power of each of these
Ocular lens is 10x
3 objective lens
Red = 4x: 40x
Yellow = 10x: 100x
Blue = 40x: 400x
what stain is used for plants
Iodine is used for plant cells
what stain is used for animals
methylene blue or crystal violet is used for animal cells.
what are the functions of the cell membrane?
Regulates entry and exit of substances, provides protection, and facilitates communication.
what is the function of the nucleus?
Contains genetic material (DNA) and controls cellular activities.
what is the function of cytoplasm?
Jelly-like fluid where cellular processes occur.
What is the function of the cell walls of plants?
Provides structure and protection
what is the function of The central vacuole of plants?
Maintains turgor pressure, stores nutrients and waste.
What are organelles?
Specialized structures within cells that perform specific functions
what is the hierarchical arrangement of organisms, cells, organelles, molecules, and atoms.
Atoms → Molecules → Organelles → Cells → Organisms.
What is the definition of a molecule?
Two or more atoms bonded together.
def of an atom
The smallest unit of an element, consisting of protons, neutrons, and electrons.
On what atom is all life on earth based?
All life on Earth is based on carbon.
what does “organic” mean?
Compounds containing carbon, usually with hydrogen and oxygen, and often with nitrogen, sulfur, or phosphorus.
how many covalent bonds can carbon form?
Carbon can form four covalent bonds. It commonly bonds with hydrogen, oxygen, nitrogen, and other carbon atoms.
What is a covalent bond?
Strong bonds formed by sharing electrons between atoms
With what other atoms
does carbon commonly bond?
commonly bonds with hydrogen, oxygen, nitrogen, and other carbon atoms.
What is a macromolecule?
Large molecule built up from smaller chemical structures
what is a polymer
A long molecule made up of repeating monomers (e.g., proteins, nucleic acids).
what is a monomer
small molecules that bond together to form more complex structures such as polymers.
what is a compound
substance made of two or more different elements chemically bonded together.
what are the four groups of organic compounds
Carbohydrates, lipids, proteins, and nucleic acids.
which of the four groups of organic compounds can not form polymers
Lipids do not form polymers. The others (carbohydrates, proteins, nucleic acids) can form polymers.
what is hydrolysis?
Breaks down polymers into monomers by adding water. (e.g., digestion of starch).
what is dehydration synthesis?
Joins monomers to form polymers by removing water. (e.g., formation of proteins from amino acids).
Of what atoms are carbohydrates composed and in what ratio?
they are composed of carbon (C), hydrogen (H), and oxygen (O) atoms.
Generally, the ratio of hydrogen to oxygen atoms in carbohydrates is 2:1, similar to water (H₂O). For example, in glucose (C₆H₁₂O₆), the ratio of hydrogen to oxygen is also 2:1.
What is a monosaccharide
The simplest form of carbohydrates, consisting of a single sugar molecule. Examples include glucose (C₆H₁₂O₆) and fructose.
what is a disaccharide?
Consists of two monosaccharide units linked together. Examples include sucrose (table sugar, composed of glucose and fructose), maltose (composed of two glucose units), and lactose (composed of glucose and galactose).
what is a polysaccharide
Complex carbohydrates composed of long chains of monosaccharide units. Examples include starch, cellulose, and glycogen.
What is a pentose
A five-carbon sugar (e.g., ribose in RNA)
what is a hexose?
A six-carbon sugar (e.g., glucose and fructose)
Sucrose
Composed of one glucose and one fructose molecule
maltose
Composed of two glucose molecules
lactose
Composed of one glucose and one galactose molecule
where’s starch found?
Found in plants; it is a storage form of glucose. Common sources include potatoes, grains, and legumes.
where’s cellulose found?
Found in the cell walls of plants; it provides structural support. It is a major component of dietary fiber.
where’s glycogen found?
Found in animals; it is the storage form of glucose in the liver and muscles.
what monomer comprises starch?
glucose
what monomer comprises cellulose
glucose
what monomer comprises glycogen
glucose
what are the characteristics of lipids
Lipids are hydrophobic or amphipathic molecules, which means they do not dissolve well in water. They include fats, oils, waxes, phospholipids, and steroids. They are important for energy storage, cell membrane structure, and signaling
what does hydrophobic mean
Water-repelling. Hydrophobic molecules do not dissolve in water (e.g., fats and oils).
what does hydrophilic mean
Water-attracting. Hydrophilic molecules dissolve in water (e.g., salts, sugars).
what does amphipathic mean
Having both hydrophobic and hydrophilic parts. Amphipathic molecules have a hydrophobic tail and a hydrophilic head, such as phospholipids.
what are triglycerides?
These are a type of lipid formed by three fatty acids esterified to a glycerol molecule.
what monomers compose triglycerides
one molecule of glycerol and three molecules of fatty acids.
what is the different between fat and oil
Fat: Typically solid at room temperature and often derived from animal sources.
Oil: Typically liquid at room temperature and often derived from plant sources
What are the major functions of fats?
Energy Storage: Fats provide a dense form of energy storage.
Insulation: Help insulate the body and organs.
Protection: Cushion vital organs.
Cell Membrane: Fats (specifically phospholipids) are crucial components of cell membranes.
What is a phospholipid and a steroid?
Phospholipid: A lipid molecule with a hydrophilic head and two hydrophobic tails. They are key components of cell membranes, forming a bilayer that acts as a barrier.
Steroid: A lipid with a structure of four fused carbon rings. Examples include cholesterol, which is important for membrane fluidity and as a precursor for steroid hormones.
Why are phospholipids biologically important?
Phospholipids are essential for forming cell membranes, while steroids play roles in signaling and membrane structure.
What are some characteristics of proteins?
Proteins are polymers of amino acids linked by peptide bonds. They have diverse functions including enzymatic, structural, transport, signaling, and defensive roles.
What is the basic structure of an amino acid?
An amino acid has:
An amino group (—NH₂)
A carboxyl group (—COOH)
A hydrogen atom (—H)
A variable R group or side chain that determines the amino acid’s properties
What is a peptide bond?
A peptide bond is a covalent bond formed between the carboxyl group of one amino acid and the amino group of another, releasing a molecule of water (dehydration synthesis).
What are the major functions of proteins
Enzymes: Catalyze biochemical reactions (e.g., amylase breaks down starch).
Structural Proteins: Provide support and shape (e.g., collagen in connective tissues).
Transport Proteins: Move substances within organisms (e.g., hemoglobin carries oxygen in blood).
Signaling Proteins: Involved in cell communication (e.g., insulin regulates glucose levels).
Defensive Proteins: Protect against pathogens (e.g., antibodies).
What are enzymes?
specialized proteins that act as biological catalysts, speeding up chemical reactions within living organisms. They are crucial for a wide range of physiological processes and biochemical reactions
What are some examples of structural proteins
Collagen: Found in connective tissues like skin, tendons, and bones, collagen provides structural support and strength.
Keratin: A key structural protein in hair, nails, and the outer layer of skin. It provides protection and durability.
Elastin: Found in connective tissues, elastin allows tissues to return to their original shape after stretching.
what are some examples of transport proteins
Hemoglobin: Found in red blood cells, hemoglobin binds and transports oxygen from the lungs to tissues and returns carbon dioxide from tissues to the lungs.
what are some examples of signaling proteins
Insulin: A hormone produced by the pancreas that regulates blood glucose levels by facilitating glucose uptake into cells.
Growth Hormone (GH): Produced by the pituitary gland, GH stimulates growth and cell reproduction.
Neurotransmitters: Such as neurotransmitter receptors (e.g., dopamine receptors) which play a role in transmitting signals across synapses in the nervous system.
what are some examples of defensive proteins
Antibodies (Immunoglobulins): Produced by the immune system, antibodies recognize and neutralize pathogens like bacteria and viruses.
What is meant by the primary, secondary, tertiary, and quaternary structure of a protein?
Primary Structure: The sequence of amino acids in a polypeptide chain.
Secondary Structure: Local folding into structures like alpha helices and beta sheets due to hydrogen bonding.
Tertiary Structure: The overall three-dimensional shape of a single polypeptide chain, determined by interactions among side chains.
Quaternary Structure: The arrangement of multiple polypeptide chains into a functional protein complex.
What is a positive vs. negative control?
Positive Control: Contains the substance being tested for and should show a positive result.
Negative Control: Lacks the substance being tested for and should show no reaction.
Differentiate between an independent variable and a dependent variable
Independent Variable: The variable that is changed or controlled in an experiment (e.g., concentration of a solution).
Dependent Variable: The variable that is measured or observed (e.g., absorbance)
What is meant by absorbance?
Absorbance: The amount of light absorbed by a solution, measured using a spectrophotometer.
what instrument is absorbance/transmittance measured?
spectrophotometer.
What is a standard curve?
A graph that shows the relationship between known concentrations of a substance and its absorbance. This can be used to determine the concentration of unknown samples by measuring their absorbance.
