dynamic science Flashcards
what is the first stage of mitosis?
- prophase
what is the second stage of mitosis?
- metaphase
what is the third stage of mitosis?
- anaphase
what is the foruth stage of mitosis?
- telophase
What is energy
energy is the abilty to do work or cause a change
what is atomic number
number of protons
what is a chemical chnage
can not be reversed, eveidence is a change in temp/colour/odour
what is size of electrons
1/1800
what is a physical change
its reverisble
what is rate of reaction
the time it takes reaction to complete
how must a chemical reaction occour
the reacting particles MUST collide with eachother. the rate of reaction depends on the frequency of reactions
what do succesful collisions rely on?
- collisions of particles
- collision with sufficient energy
- efficient orientation of collision
how does temperature infulence reaction rate?
as temp increases, the kenitic energy in particles increases causing them to move faster making them collide faster
how does surface area infulence reaction rate?
if you increase surface area, rate of reaction increases as there is more area for particles to collide
how does a higher concentration infulence reaction rate?
at a higher concentration, there are more particles in the same amount of space causing for more collisions to occour
how does a catalyst infulence reaction rate?
a catalyst is a chemical that speeds up reactions as it provides a different route for collisions.
what is the endocrine system
maintains balance in the body through the action of hormones
how do hormones travel
through the blood stream
what is endocrine system made up of?
endocrine glands that secrete chemical messenger called hormones
do hormones work on all cells?
no, only on target cells that has designated receptors that recognize the hormones they need
how are hormones released?
controlled by external and internal and stimuli
what is hypothalamus
it detects changes in temp and is located in brain
pituitary gland -
- master gland
- secrets growth hormone
thyriod gland -
- regulates metabolism
- secrets thyroxine
adrenal gland
- flight or fight respone
- secretes adreneline and cortisol
pancreas
- regulates blood sugar levels
- secretes insulin and glucagon
(insulin takes glucose from blood stream, glucagon puts blood sugar back into blood)
ovaries
- controls female charactsics
- secretes oestrgoen and progestrone
testes
- controls male characrsics
- secretes testostrone
pineal
- controls sleeping and waking patterns
- secretes melatonin
what conditions in the body are kept constant
- body temp (37)
- amount of water in the body
- blood sugar levels
what is the stimulus respone model
- stimulus
- receptors
- control centre
- effector organs
- respsone
what is negative feedback
is a response to a changed enviroment that reverses changes
what is a gene
segment of dna that codes for a specific protein
what is a chromosome
a molecule/dna strand
what is diabtetes
diabtetes is when your body doesnt produce enough inuslin causing for too much blood sugar to be in your body.
RNA properties
can leave nucleas,
base p[airs = A+U, C+G
base pairs of DNA?
adenine + thymine
gaunine + cytosine
what are the 2 steps of protein synthesis?
- transcription (DNA-mRNA)
- translation (mRNA-protein)
Why do cells replicate
to grow, repair and replace dead damged or infecrted cells.
How do you make a protein
mRNA is copied from the DNA in the nucleus and carries the insutctions for one gene to the cytoplasm where proteins are made at the ribosome
what are the main steps of the cell cycle?
- interphase
- mitosis
- cytokeniss
what happens in G1
growth period before dna syntheis, makes proteins
what happens in interphase?
- G1
- DNA synthesis
- G2
why is DNA replicated
to ensure that a cell hsa 2 copies of dna before it divides
what is step 1 of dna syntheies?
UNZIPPING OF PARENT DNA
- enzyme helicase breaks hydrogen bonds between bases
- both strands are now template strands
what happens in DNA syntheis?
DNA is replicated.
what is step 2 of dna syntheis?
FORMATION OF NEW DAUGHTER DNA
- new base paires pair with each strand of parent DNA
- enzyme polymerase joins adjacent nucleotides to from sugar phosphate backbones
what is dna replication
semi-conservative
what happens in G2
period after DNA syntheis but before mitois, still growing
how does cytokenins occour in plant cells
cell plate
what is a checkpoint
checkpoints will prevent cell division if
- cell is short of nutrients
- DNA has not been replicated
- DNA is damages?
how does cytokenins occour in animal cellsz?
cleavage furrow
where are the checkpoints
just after G1 before S, just after G2, before mitosis, mitosis checkpoint
what can happen if a mutation occours
mutations in genes can result in an out of control cell cycle due to a lack of checkpoints that could result in cancer
what happens in the first stage of mitosis
Prophase -
chromsomes coil, become more visible, nuclear membrane starts to dissapear
what happens in the third stage of mitosis
Anaphase -
sister chromotids are pulled to opposing poles of the cell by spindle fribes
what happens in the second stage of mitosis
Metaphase -
nuclear membrane is completly gone, chromorids are pulled by spindle fibres to the equator of a cell
what happens in the fourth stage of mitosis
Telophase -
sepeartion of chromosomes is complete, nuclear membrane reforms, chromsomes unciol
what is cytokesins
division of cell after mitosis
what are somatic cells
cells that are diploid meaning they carry 2 sets of chromosome from each parents
what is energy measured in
joules
what are the 9 energy forms
- heat
- light
- sound
- nuclear energy
- kinetic
- gravitational potential
- elstatic potential
- chemical potential
- electrical
what are the main types of energy
kinetic ( energy due to motion )
potential ( stored energy in an object )
what energy forms are potential
chemical energy, nuclear energy, gravitiational potiential, elastic potenital
what is work
the amount of energy it takes to perform a task
what energy forms are kinetic
electrical, light, sound, heat
what is the conservation of energy rule?
energy cannot be created or detoryed. whenever energy is converteted from one form to antoher, the total energy remains constant.
what is the transformation of energy
energy changes from one form to another
what is a transfer of energy
energy is passed along
what is thermodynamics
is the study of how heat (thermal energy) can be tranformed or tranfered between opbjects
what does thermal energy cause for
particles to vibrate
what is a thermodyncamic system
thermodynamic enegery is the total energy of all moving or vibrating particles in an object
how is thermal energy tranfered
when a hot object cools, the thermal energy is transfer from the molecules on the hot object to the air paritcles
what are the 3 thermal energy transfers?
- conduction
- convection
- radiation
which way does heat flow
heat flows from where it is hotter to where it is cooler
define conduction
occours when two objects at different temperatures are in contact with eachother
define convection
is the transfer of heat by the movement of a fluid (liquid or gas) between areas at diffferent temp
define radiation
heat energy transfered by infared radiation, which is is in the form of waves
what types of cells undergo mitosis
all cells except for sex cells
what colour does lithium go
red
what colour does copper go
green
