Science Flashcards
who discovered cells
Robert Hooke
When did Robert Hooke discover cells
1665
who invented the microscope
Antonie van Leeuwenhoek
What is in a plant cell
cell membrane, chloroplast, cell wall, vacuole, nuclease, mitochondria, cytoplasm
What does mitochondria do
creates energy from glucose
what does the vacuole do
helps dispose waste and stores cell sap
what does chloroplast do
produces energy from photosynthesis
what is a eukaryotic cell
a complex cell, with a nucleus
what do ribosomes do
make protiens
what does an animal cell have
cell membrane, cytoplasm, ribosomes, nucleus, mitochondria
what does a bacteria cell have
slime coat, chromosomal DNA, cell wall, cell membrane, cytoplasm, plasmid, flagellum
what does the slime coat do
traps nutrients
what does plasmid do
contains a small part of the bacteria’s DNA
what does Chromosomal DNA do
Helps with self replication
what is mitosis
a process where a cell divides and replicates into two identical daughter cells
What are the 5 stages of mitosis
prophase, metaphase, anaphase, telophase, cytokinesis ( PMAT)
What happens in the prophase
nucleus breaks down and spindle fibres start to appear
what happens in the metaphase
the chromosomes line up on the spindle fibres across the middle of the cell
what happens in the anaphase
the chromosomes separate and move to opposite ends of the cell
what happens in the telophase
a membrane starts to form around each set of chromosomes
what happens in cytokinesis
a cell surface membrane forms around the two new cells
what is cell differentation
a process that changes less specialised cells into more specialised cells
why are some cells biconcave
to increase the surface area
what are alleles
different forms of the same gene
what is a dominant allele
the stronger allele
what is a recessive allele
the alleles that aren’t dominant
what is the formula triangle you use for magnification
actual image size, picture size, magnification
what is matter made up of
tiny particles called atoms
What are two rules about atoms
- atoms cannot be created or destroyed
- atoms in an element are all identical
what is an atom made up of
shells, protons, neutrons
what does the nucleus in an atom contain
protons and neutons
what charge does a proton have
positive (+1)
what charge does an electron have
negative (-1)
what charge does a neutron have
no charge (0)
what is the atomic mass number ( bottom )
total number of protons a neutrons
what is the atomic mass ( top )
tells us the number of protons in the atom
what are isotopes
different forms of the same element
what is electronic configuration
where the electrons are placed in the shells
how many electrons are in the first shell
2
how many electrons in the the rest of the shells
8
who invented the periodic table
Dimitri Mendeleev
how did Mendeleev organise the elements in the periodic table
in order of their relative atomic mass
how can you find out what group an element is in
the same number as the amount electrons are in the outer shell
how do you find out what period an element is in
the period number is the same as the amount of shells an atom has
what is a physical change
a change where only the physical form is changed, and no new substance is created
what is a chemical change
a change where a new substance is created
what is a mixture
something that contains elements that aren’t chemically joined together
on a temperature - time graph, what does it mean when the line is horizontal
it shows that the temperature is consistent, which means the substance is changing state
how do you know if a substance is pure
all parts will melt at the same temperature
what happens when you heat up a substance
the particles gain energy, and break away from their fixed arrangement
what does soluble mean
is able to dissolve in water
what does insoluble mean
cannot be dissolved in water
what is a solvent
the liquid that something dissolves in
what is a solute
the thing that is being dissolved
what is a solution
a mixture of the solute and solvent
what is crystillation
where you heat a filtrate until crystals from
what does paper chromatography do
separates inks and dyes
what is the mobile phase in paper chromatography
the solvent
what is the stationary phase in paper chromatography
the paper
what is the Rf value
is a ratio used to describe the distance a component in a mixture travels in relation to the distance the solvent travels.
what is distillation
something used to separate liquids with different boiling points
how do you work out the rf value
distance travelled by spot divided by the distance travelled by solvent (answer must always be below 1)
what is fractional distillation
something used to separate two or more liquids
what is a vector quantity
a type of measurement that includes magnitude ( size ) and direction
what is a scalar quantity
a type of measurement that only includes magnitude
3 examples of a vector quantity
force, velocity, acceleration
what is velocity
speeding in a specific direction
3 examples of a scaler quantity
speed, distance, time
what is displacement
displacement is a straight line form A to B. for example, if you are driving on a road, it normally has bends in, but the displacement would just be a straight line there
how do you work out the gradient of a distance time graph
y axis divided by x axis
what are resultant forces
the resultant force is the stronger force, so for example if it was 12N to the right and 3N to the left, the resultant force would be 9N to the right
how do you work out the weight of something
weight = mass x gravitational field strength
