assessment #1 Flashcards
What are some characteristics of life?
- at least 1 cell
- need energy (metabolize nutrients to make ATP) to survive
- respond to stimuli in their environment
- able to reproduce
- can grow and develop
- have a universal genetic code
- maintain homeostasis
- adapt and evolve over time
autotrophs
organisms that make their own nutrients using solar energy
heterotrophs
organisms that get energy by consuming nutrients from the environment
sexual reproduction
two sex cells needed to reproduce
asexual reproduction
only one sex cell is needed to reproduce
Adapt and evolve over time
Evolution is a gradual change in a population of organisms over generations
maintain homeostasis
homeostasis-a relatively stable internal environment (within a certain range)
negative feedback can help maintain homeostasis
What do DNA and RNA do?
pass on genetic info
What charges attract?
opposite
What charges repel?
similar
Define intermolecular forces and give an example.
forces occur between molecules, hydrogen bonds, van der Waals interactions
Define intramolecular forces and give an example.
forces occur within molecules, covalent bonds
hydrogen bond
- weak attraction between 2 polar molecules
- forms between H on one molecule, and O, N, or Fl on another
cohesion
- when water molecules are attracted to themselves due to their polarity
- helps create surface tension
adhesion
- water is attracted to other polar/charged particles
capillary action
water moving upwards through tight spaces due to cohesion and adhesion working together
amphipathic
- has polar and nonpolar regions in the same molecule
POV: You have a petri dish with fresh tap water. You use a plastic fork to try to float a clean, dry paperclip on the surface of the water. Then, you add some dish detergent solution to it. What is happening and why is this happening?
The paperclip floats at first, but when the soap to it, the paperclip moves to the edge and then immediately sinks. At a molecular level, surface tension is what is keeping the paperclip afloat. Soap is amphithatic, meaning it has both polar and nonpolar regions. Water molecules were attracted to the polar end of the soap molecules. This caused the hydrogen bonds to break and the surface tension goes away, allowing the paperclip to sink.
POV: You have a glass slide and you drop some water on it. You have a clean piece of wax paper and you drop some water on it. What is happening and why is this happening?
The water slides down the glass in drips and leaves trails behind because adhesion is causing the water, a polar substance, to be attracted to glass, a polar substance. With the wax paper, the water drips down in a single ball and leaves no trails behind because wax is a nonpolar substance, so the water is not attracted to it. This allows the water to be attracted to itself (cohesion)
POV: You have a vial with water and oil in it. What is happening and why is this happening?
Oil is nonpolar and water is polar, so they are not attracted to each other, but they are attracted to themselves via cohesion.
POV: You have a wet piece of yarn and you have water in the bottom of a small beaker. You hold one end of the string in the small beaker. You slowly pour. What is happening and why is this happening?
The water flowed in capillary action, along the piece of yarn. Adhesion worked with cohesion. Cohesion caused the water to stay together and adhesion caused it to be attracted to the polar yarn.
covalent bonds
when atoms fight over their electrons and therefore are bonded
atoms
- made up of protons, neutrons, and electrons
- make up molecules
molecules
- made up of atoms
- bonded covalently
