Topic #3 Flashcards
What is the difference between distance and displacement?
Displacement
Displacement describes the change in position of an object and its direction over a certain period of time.
Distance
Distance is how far an object travels over a certain period of time
Displacement uses direction (NSEW)
Distance uses scalar quantity (m,km)
Speed unit conversion
m/s > h/s (multiply by 3.6)
h/s > m/s (divide by 3.6)
How do you calculate average speed?
Total distance/Total time
Or use motion triangle (d,s,t)
How do you calculate average velocity?
Displacement/time
V=x/t
How do you calculate average acceleration and acceleration?
Average acceleration = change in speed/time taken
Acceleration = final speed – initial speed/time taken
v – u/t
What unit is force measured in?
Newtons (N)
Forces cause objects to:
- start or stop moving (accelerate or decelerate)
change speed or direction
- bend, stretch, twist or change shape
- changes in motion of an object cannot takes place without a force acting on it.
What is Newtons First law?
Anything at rest or at a constant velocity will stay that way unless a force acts on it.
(Law of Inertia)
What is Newtons Second law?
Force = mass x acceleration
F=ma
Where:
F is net force on object (N), m is mass of object (kg), a is acceleration (m/s2)
What is Newtons third law?
“For every action force there is an equal and opposite reaction force.”
What are chromosomes?
Chromosomes are structures found in the nucleus of a eukaryotic cell.
What is DNA?
DNA is Deoxyribose Nucleic Acid.
DNA is a a double helix molecule. (twisted ladder).
DNA is made up of sub-units (building blocks) called nucleotides.
Structure of a DNA nucleotide
A deoxyribose molecule (5 carbon sugar).
A phosphate group (PO4).
A cyclic nitrogenous base – either adenine, guanine, cytosine or thymine.
Phosphate is small
Deoxyribose is pentagon
What are the complementary bases held together by?
Hydrogen bonds
What is a gene?
A gene is a unit of heredity that is passed from parent to offspring and determines the characteristics of an organism.
What does the helicase do when replicating DNA?
It breaks the hydrogen bonds between the bases.
