exam 1 (review slides) Flashcards
basic characteristics of living things
ordered complexity
body composed of different kinds of cells, each containing complex molecular structures
- well-organized team working together towards a common goal
basic characteristics of living things
sensitivity
respond to stimuli in environment
basic characteristics of living things
growth, development, and reproduction
inherited information carried by genes to offspring
- controls pattern of growth and development
basic characteristics of living things
energy utilization
take in energy and use it to perform work
via metabolism (all chemical reactions that occur within cells of living things)
basic characteristics of living things
homeostasis
maintain relatively constant internal conditions that are different from their environment
reductionism
approach that reduces complex systems to simpler components that are more manageable to study
systems biology
analyzing interactions among the parts of a biological system
- used to study life at all levels
- allows biologists to predict how a change in 1 or more variables will affect other components as well as the whole system
structure & function
- analyzing biological structure gives clues about what it does and how it works
- structure always determines function
2 characteristics of all cells
- enclosed by a membrane that regulates passage of materials between cell and environment
- uses DNA as their genetic information
prokaryotic vs. eukaryotic
prokaryotic: single-celled, lack nucleus or other membrane enclosed organelles
eukaryotic: membrane-enclosed organelles
feedback regulation + 2 types
output, or product of a process, regulates that very process
negative feedback: a loop in which the responses reduces initial stimulus (ex. insulin and glucose levels)
positive feedback: end product speeds up its own production (ex. clotting of blood in response to injury)
evolution
living organisms are modified descendants of common ancestors
process of biological change in which species accumulate differences from their ancestors as they adapt to different environments over time
taxonomy
branch of biology that names and classifies species into groups of increasing breadth
Charles Darwin’s main 2 points
- species showed evidence of “descent with modification” from common ancestors
- “natural selection” is the mechanism behind descent with modification
qualitative vs. quantitative data
qualitative: recorded descriptions rather than measurements
quantitative: recorded numerical measurements, which are sometimes organized into tables and graphs
hypothesis
an explanation, based on observations and assumptions, that leads to a testable prediction
- must lead to predictions that can be tested by making additional observations or by performing experiments
controlled experiment
an experiment designed to compare an experimental group with a control group
- the 2 groups differ only in the factor being tested
independent vs dependent variable
independent variable: factor being manipulated by researchers
dependent variable: factor being measured that is predicted to be affected by independent variable
compound
substance containing of 2 or more different elements in a fixed ratio
- has characteristics (emergent properties) different from those of its elements
element’s atomic number
of protons in its nucleus
element’s mass number
sum of protons + neutrons in nucleus
atomic mass
number of protons, can be approximated by mass number
isotopes
different atomic forms of the same element
- same # of protons, different # of neutrons, thus differing in atomic mass
how valence electrons impact atom interactions
atoms interact in a way that completes their valence shells
reactivity of an atom arises from the presence of unpaired electrons
90% of the time, electrons are found in ________
orbitals
covalent bond
sharing of a pair of valence electrons by 2 atoms
- strongest chemical bonds (individually)
single vs double covalent bond
single covalent bond: sharing of 1 pair of valence electrons
double covalent bond: sharing of 2 pairs of valence electrons
electronegativity
atom’s attraction for electrons in a covalent bond
- the more electronegative an atom is, the more strongly it pulls shared electrons toward itself
nonpolar covalent bond & polar covalent bond
nonpolar: atoms share electrons equally b/c 2 atoms have the same electronegativity
polar: 1 atom is more electronegative, and electrons are not shared equally
- unequal sharing of electrons causes a partial positive or negative charge for each atom or molecule
ionic bonds
more electronegative atoms sometimes strip electrons complete away from their bonding partners
- resulting oppositely charged atoms or molecules are called ions (anions and cations attract each other, this attraction is called an ionic bond)
THEY SELFISH
hydrogen bonds
hydrogen bond covalently bonded to 1 electronegative atom
- hydrogen atoms have partial positive charge that attracts a diff electronegative atom with a partial negative charge nearby
in living cells, electronegative partners are usually oxygen or nitrogen atoms
Van Der Waals interactions
very weak bonds that exists between all molecules
(electrons are not always evenly distributed and may accumulate by chance in one part of a molecule resulting in regions of positive and negative charge that enable all atoms and molecules to stick to one another)
individually weak but can be collectively strong
interactions are very weak, aka reversible
- van der Waals exist in tertiary protein structures –> create functional proteins
the effects of molecular shape
molecular shape determines how biological molecules recognize and respond to one another with specificity
ex. morphine and endorphins have similar effects b/c their shapes are similar and bind to the same receptors in the brain