Science Flashcards
What are the differences between light microscopes and electron microscopes?
light:
-samples are generally dead
-images are in 2D
-sometimes requires a stain
-very thin samples
electron:
-samples are dead
-images are in 3D
-has higher magnification
-thin samples are needed
What is the formula for work done?
Work done = force(n) x Distance(m)
What is active transport?
The movement of molecules across a cell membrane from an area of low concentration to high concentration with the use of energy.
What are the properties of a metallic structure?
-Hight melting point
-cannot dissolve
-can conduct electricity
state 3 ways to make a test reliable
-Repeat the experiment
-Accurately record data
-have equal sample sizes
What is a compound?
A substance made up of 2 or more different elements (chemical bonds)
What are the 5 energy stores and what do they mean?
Kinetic- anything that moves
gravitational- anything that can fall
elastic- anything that can stretch or change shape
chemical- anything with energy from reactions or food
electrical- objects with electrical charges which can repel or attract
What is a stem cell?
Un-specialised cells that can turn into different specialised cells (found in bone marrow)
Describe the function and adaptations of the specialised cell villi
Function:
Used for the absorption of food in the small intestine.
Adaptations:
has microvilli for increased surface area for faster absorption of food
Describe the function and adaptations of the ciliated epithelial cell (a specialised cell)
Function:
Allows particles to be trapped and moved along in the respiratory tract (organs involved in breathing)
Adaptations:
Has small hairs on top of the cell to move
What is the Formula for power?
Power(w) = work done(j) / Time(m)
What are the properties of Diamond and graphite?
Diamond:
-4 covalent bonds
-tetrahedral structure
-cannot conduct electricity
-extremely high melting point
Graphite:
-3 covalent bonds
-layers of hexagonal rings
-can conduct electricity
- easily sliding layers
-high melting point
Describe the function and adaptation of nerve cells (specialised cell)
Function:
to transmit signals in the nerve system
Adaptation:
-has branched connections at each end
-is thin and long to carry messages quick
What are the 3 variables?
Independent- What you change
Dependent- What you measure
Control- What you keep the same
What is ionic bonding?
The bonding that takes place between non-metals and metals (electrostatic attraction)
State 3 properties of Iconic substances
-They form lattice structures
-They have high melting points
-They can conduct electricity when dissolved
-They are soluble in water
What is Diffusion and Osmosis?
Diffusion:
The movement of particles from an area of high concentration to an area of low concentration
Osmosis:
The movement of water from an area of high concentration to an area of low concentration through a partial permeable membrane.
Describe the steps to Mitosis (the duplication of cells)
Prophase:
cell is resting
Metaphase:
Chromosomes make there copies on the equator of the cell
Anaphase:
The chromosome copies are pulled to either end of the cell
Telophase:
A new membrane starts to form around each new cell
Cytokinesis:
The membrane between the cells pinch and two new identical cells are formed
How do you find the mean of data?
You add up all the numbers and divide the total by however many numbers there was at the beginning
State the 10 parts of a microscope
-Eyepiece
-Objective lens
-Coarse focus
-Stage clip
-Stage
-Arm
-Condenser
-Light
-Mirror
Describe the function and adaptations of red blood cells (specialised cell)
Function:
To carry oxygen around the body
Adaptation:
-It has a dip in the middle for a larger surface area for more oxygen
-Has no nucleus for more oxygen
What is the electronic confiruration?
The number of electrons in each shell of an element. E.g-> Carbon= 2,4,2
What is metallic bonding?
The electrostatic attraction between a positive metal ion and a negative electron
State the organelles in an animal cell and there function
Cytoplasm- Where chemical reactions take place
Nucleus- Holds DNA and controls the cell
Mitochondria- Where respiration occurs (energy)
Ribosomes- Stores protein
Cell membrane- controls what goes in and out the cell
