BIO TEST Flashcards
What are the steps in the scientific approach?
Exploration -> investigation -> communication
What is a guess?
An assumption with no critical evidence
What is a hypothesis?
An educated guess (look for because)
What is a prediction?
A statement of what will happen next in a sequence of events.
Often caused by the hypothesis.
What is an independent variable?
The factor that is changed or manipulated during an experiment
What is a dependent variable?
The outcome factor; the variable that may change in response to manipulations of the independent variable.
What are controlled experiments?
An experiment in which only one variable is changed/manipulated
What are comparative experiments?
Experiments that look for differences between samples or groups
What are the characteristics of living organisms?
- Consists of one or more cells with organelles
- Contains genetic program
- Grow and reproduce
- Harvest, transform and use energy/chemical building blocks
- Respond to their environment
- Evolve
What are the 4 most common chemical elements in living organisms?
Carbon, hydrogen, oxygen, nitrogen
What are carbohydrates?
Macromolecules that provide energy with simple sugars and form cell walls.
Molecular subunits (monomer): monosaccharides.
What are lipids?
Macromolecules used for long-term energy storage, structural components of cell membranes, and hormones.
Molecular subunits (monomer): fatty acids.
What are nucleic acids?
Macromolecules that hold and transmit genetic information.
Molecular subunits (monomer): nucleotides.
What are proteins?
Macromolecules that perform many functions including structural support, enzymatic catalysis, and transport.
Molecular subunits (monomer): amino acids.
What is a covalent bond?
A bond formed by the sharing of electrons between atoms
What are ionic bonds?
Bonds formed when one atom completely transfers electrons to another, creating oppositely charged ions that attract each other.
What are hydrogen bonds?
Weak bonds between oppositely partially charged sides of two or more molecules.
Why are valence electrons important?
They are the outermost electrons of an atom involved in sharing or transferring with other atoms to achieve a stable electron configuration.
What is a polar covalent bond?
A covalent bond in which electrons are not shared equally.
How do polar covalent bonds and hydrogen bonds contribute to water’s properties?
Polar covalent bonds hold oxygen and hydrogen together, while hydrogen bonds attract water molecules.
What does hydrophilic mean?
Water loving; polar molecules that are positively or negatively charged and dissolve in water.
What does hydrophobic mean?
Water fearing; non-polar molecules that do not have a charge and associate with other non-polar molecules.
What is the relationship between hydrogen ion concentration, the pH scale, and acidic/basic solutions?
- pH affects many chemical reactions and biological processes
- Water contains some hydroxide ions and some protons
- pH refers to the concentration of protons (-log[H+])
- Protons are the same as hydrogen ions.
What is the carboxyl group (-COOH)?
Polar, hydrophilic, behaves as a base, positively charges cells.
Found in fatty acids, amino acids, proteins.
What is the amino group (-NH2)?
Polar, hydrophilic.
Found in amino acids, proteins.
What is the hydroxyl group (-OH)?
Polar, hydrophilic (alcohol).
Found in amino acids, proteins, and carbohydrates.
What is the methyl group (-CH3)?
Non-polar, hydrophobic.
Found in amino acids, proteins, nucleic acids.
What is the sulfhydryl group (-SH)?
Polar, forms S-S bonds.
Found in cysteine, proteins.
What is the phosphate group (-OPO3H2)?
Polar, negatively charged, hydrophilic.
Found in phospholipids, nucleic acids, ATP.
What are the functions of complex carbohydrates?
- Starch stores glucose in plants
- Glycogen stores glucose in animals
- Cellulose maintains cell walls in plant cells.
What is the difference between simple sugars and complex carbohydrates?
Simple sugars (monosaccharides) are single sugar molecules, while complex carbohydrates are chains of multiple sugar molecules linked together.
How is a glycosidic linkage formed?
A covalent bond that joins sugar molecules to each other or to other molecules, releasing water as the bond forms.
Compare starch, glycogen, cellulose, and chitin.
- Starch and glycogen are energy storage molecules; glycogen is found in animals, starch in plants.
- Cellulose and chitin help build cell membranes; cellulose is found in plants, chitin in some insects.
What are triglycerides?
Lipids used for energy storage.
What are phospholipids?
Lipids that form cell membranes.
What are steroids?
Lipids that act as hormones.
Where are lipids synthesized in eukaryotic cells?
In the endoplasmic reticulum (ER) of cells.
What does it mean if a triglyceride is saturated or unsaturated?
Saturated means it has no double bonds (solid), while unsaturated has double bonds (liquid).
Why are phospholipids considered amphipathic?
They have hydrophobic tails and hydrophilic heads.
How does sample size affect the quality of a scientific study?
The larger the sample, the more reliable the conclusions.
