Introduction to Biology

Temperature

the motion of the particles that make up an object

the law of inertia

states that an object at rest stays at rest, and an object in motion stays in motion unless acted upon by a net external force.

The action reaction law

states that for every action, there is an equal and opposite reaction, meaning forces always occur in pairs.

the law of acceleration

states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

When an object of a mass is moving at a velocity its momentum is…..

mv

when an object of mass is moving at a velocity its kinetic energy is

½ mv2

acceleration formula

is defined as the change in velocity per unit time.

a= v2-v1/ t

what is the formula for impulse

Ft = mv2 -mv1

Important formula

Ft = mv2 - mv1

what is carbon-14 dating

• organisms incorporate 14C to their body through photosynthesis and food chain. the 14C ratio in their body will be the same as that of the atmosphere

• once the organism dies, no new carbon atoms will be taken into its body, which 14C keeps decaying

• by measuring the 14C ratio of a dead body, we can tell how many years ago it died

Define an isotope

atoms with the same number of protons but different number of neutrons

define speed

how fast something moves

define velocity

how fast but also which direction something moves

what is the equation for displacement

Displacement = Velocity X time

define velocity

the change of displacement per time

define acceleration

The change of velocity per time

what is a Vector

objects which have direction and magnitude

what is a scalar

object with only magnitude

what are vectors shown as in physics

they are shown in a sum of two perpendicular vectors

define an element

substance that cannot be broken to other substances by chemical reaction

define compounds

a substance consisting of two or more different elements combined in a fixed ratio

ionic bonds

• An ionic bond is a strong attraction between two oppositely charged ions

• formed when one atom transfers electrons to another atom.

covalent bonds

• Formed when two or more atoms share

one or more pairs of electrons

• Covalent bonds are very strong (require

lots of energy to break)

• A group of atoms held together by

covalent bonds is called a molecule

where are noble gasses found on the periodic table

they are found on the right side of the periodic table

what is a single covalent bond

atoms connected with a single bond can rotate against each other (balls connected by bar)

double covalent bonds

those connected with a double or triple bond cannot (two balls connected by two or three bars)

Electronegativity

• strength in the tug-of-war

• larger the electronegativity the stronger the bonds

define Polarised

he unequal sharing of electrons in a bond or the distortion of an electron cloud around an atom or ion

define non polar

electric charges are distributed equally with no positive or negative poles

What is a hydrogen bonds

froms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom

what is van Der Waals interactions

weak, attraction or repulsion between atoms and molecules.

hydrophilic interactions

• polar molecules can electrically interact with water molecules

hydrophobic interactions

• non polar molecules such as methane shown in B are hydrophobic

• binding between hydrophobic molecules because of the lack of electrical polarity is called hydrophobic interactions

what is cohesion

the attractive force that holds molecules of the same substance together

what is adhesion

• the tendency or ability of dissimilar particles, molecules, or surfaces to cling and stick to one another

what is surface tension

• is a measure of how difficult it is to break the surface of a liquid

• water has an unusually high surface tension due to hydrogen bonding between the molecules at the air water interface and to the water below

why does ice float on water

it is very peculiar

what temperature does water reach its greatest density

4 degrees

why else does ice float in liquid water

• because hydrogen bonds in ice are more ordered, making ice less dense than water

define a Solution

• is a liquid that Is a completely homogeneous mixture of substance

define a solvent

• is the dissolving agent of a solution

define a solute

• this is the substance that is dissolved

define an aqueous solution

• ia homogeneous mixture where water acts as the solvent to dissolve one or more substances

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define a freen solvent

• water is a versatile solvent du to its polarity

• it is when an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules called hydration shell

what do acids donate in aqueous solutions

• They will donate H +

what do bases donate in aqueous solutions

• They donate OH- or accept H+

what is the equation for neutralisation

H+ + OH- → h2O

• strong biases and acids dissociate completely in water

• weak acids and bases reversibly release and accept back hydrogen ions

• a shift in the balance of H+ and OH- away from neutrality can still occur

define mol/L

it is related to the number of molecules, rather than their weight

define atomic weight

the weight of a single atom

what is the number used to calculate mol and what is its scientific name

• 6 × 1023

• Avogadro number

what is the ph value for various solutions

acids, PH <7

neutral, PH = 7

Bases, PH >7

what is the relationship between H+ and OH-

• in any aqueous solution at 25 degrees it is known that the following equation stands

• (H+)(OH-)= 10-14

what Is ocean acidification?

• humans generate 25% Co2 which is absorbed by the oceans

• the co2 dissolves in seawater reacts with water and forms H+

• (CO2 + H2O → H+ + HCO3-)

what are buffers

• they are substances that minimise changes in concentrations of H+ and OH- in a solution

• working to keep the internal PH of most living cells to 7

blood buffering system

define polymers

• long carbohydrates

• proteins

• nucleic acids

non-polymers

• simple carbohydrates (sugar)

• lipids

what do sugars make

• sugar monomers make carbohydrates

what are sugars stored as

• they are stored as polymers

when there is extra sugar in our body, what is it stored as?

it is stored as fats (lipids)

What are Enzymes roles

• they are crucial in digesting sugars

• turning it into fat

what are proteins made of

• they are made up of amino acids

properties of DNA

• contains deoxyribose

• forms double strands

• 4 bases are : A, T, G, C

properties of RNA

• contains ribose

• mainly forms single strands

• 4 bases are : A, U ,G, C

which bases bind to which base

A → T/U

G → C

what are the three main carbohydrates we have learnt about

• monosaccharides

• Disaccharides

• Polysaccharides

what is the role of aldehyde group?

They make easier chemical bonds with other molecules

what can aldehyde group lead to? (negative)

• it can cause uncontrollable binding to many proteins

• this could lead to protein function impairment

• can cause diseases such as diabetes

Diabetes

• it damages nerves, blood vessels and any cells

it can cause…….

• blindness

• stroke

• non-healing wounds

• limb amputation

why do we store fat in our bodies

• a gram of fat stores more than twice as much energy as a gram of polysaccharides, such as starch

• plants do not move, this is because there is little need for compact energy sources for them

• that’s why fats are more likely to be found in animals than plants

define steroids

• these are lipids characterised by a carbon skeleton consisting of four fused rings

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what is cholesterol?

• a type of steroid

• a component in animal cell membranes

• a precursor from which other steroids are synthesised

• HOWEVER, an excess level of cholesterol in the blood may contribute to cardiovascular disease

• called a steroid due to its carbon fused rings

what is triglyceride

• a glycerol molecule attached to 3 hydrogen chains

• they are highly hydrophobic

• they are unsaturated and saturated fats