AQA A level Biology Unit 1 Notes

7/24/2019 AQA A level Biology Unit 1 Notes

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DigestiveOrgan

Function

SalivaryGlands

1) Near mouth2) Produces amylase

Oesophagus 1) Carries food from mouth to stomach2) ade up of thic! muscular "all

Stomach 1) uscular sac "ith an inner layer that produces en#ymes2) Stores and digests food$ especially proteins%) &as glands that produce en#ymes to digest protein

') Other glands produce mucus to stop actual stomach from (eingdigested

Pancreas 1) arge gland (elo" stomach* produces secretion called pancreatic+uice2) secretes protease to digest proteins$ lipase to digest lipids$amylase to digest starch

Small,ntestine

1) ong muscular tu(e2) Food is further digested (y en#ymes%) &as microvilli to increase surface

arge,ntestine

1) -(sor(s "ater2) most of "ater comes from secretions of digestive glands

%) Food (ecomes drier and thic!er* forms faeces.ectum 1) Final section of intestines* faeces stored (efore egestionStarch /i0e0 sugars) is !no"n as a Polysaccharide as it is a long chain of monosaccharides

+oint together$ "hereas a disaccharide is +ust t"o monosaccharides +oint together0

Glucose C3&12O3Disaccharides

Glucose 4 Glucose 5 altose Glucose 4 Fructose 5Sucrose Glucose 4 Galactose 5

actose

S,P,F,6D 76.S,ON

&o" is

D,S-CC&-.,D6 made from 89O

ONOS-CC&-.,D6S Condensation /.emoving&2O)

G:COS,D,C ;OND

&o" are 89O ONOS-CC&-.,D6S made fromD,S-CC&-.,D6 Hydrolysis /-dding &2O)


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&o" Starch Digestion ta!es place

1) Salivary amylase hydrolyses starch to maltose in the mouth02) Pancreatic amylase in the pancreas further hydrolyses starch to maltose%) ,n small intestine$ epithelial cells produce en#yme called maltase "hich hydrolyses

maltose to glucose and glucose (y (rea!ing the glycosidic (ond0actose ,ntolerance

1) 6pithelial cells cannot produce en#yme called lactase2) actose cannot therefore (e

hydrolysed%) icroorganisms (rea! do"n

lactose* microorganisms respireand therefore produce car(on

dio


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- car(ohydrate is a compound that contains car(on$ hydrogen and o


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o" Su(strate Concentration

1) 8oo fe" su(strate molecules2) Not all active sites occupied%) .eaction only half of ma;ric! .ed

Colour

Non.educing

Sugar /all other

disaccharides)

;enedictHs .eagent$

then

&ydrochloric -cid$

-dd ;enedictHs .eagent to

2cm%of test solution0 ,f colour

does not change$ add &Cl$

this "ill hydrolyse

Orange>;ric! .ed

Colour


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then

Sodium &ydrogen

Car(onate$ then

once again

;enedictHs .eagent

disaccharide into

monosaccharide$ then add

Sodium &ydrogen Car(onate

to neutralise acid$ then add

;enedictHs solution0

Protein

/Polypeptide)

;iuret Solution*

Sodium &ydro


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helps in the complete (rea!do"nof cells after their death /autolysis)0

.i(osomes Site of protein synthesis0 8hey ma!eproteins for e


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2) Phospholipids* contain 2 fatty acids /hydropho(ic) and 1 phosphate head

/hydrophilic) attached to Glycerol molecule via condensation

6mulsion test for ipids 1) Grind sample "ith 6thanol2) -dd "ater and sha!e gently%) -n emulsion is formed and solution goes cloudy

Saturated Fatty -cid No dou(le (onds (et"een car(on and car(on atoms in a fatty acidchainBnsaturated Fatty -cid One Dou(le (ond (et"een car(on and car(on atoms in a fatty acidchainFunction of Cell em(rane 1) Permit uidity

2) Selectively transport su(stances

%) .ecognition /(iochemical reactions)') aintain integrity of cell) Compartmentalise

Functions of Protein in Cell em(rane 1) aintain cellHs shape2) Catalyse reactions in cytoplasm%) .ecognition') 8ransport su(stances) .eceptors

6ndocytosis 8ransport of materials into the cell06


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') -ctive 8ransport ovement of su(stance through the carrier/only carrier) intrinsic proteinof a partially permea(le mem(rane "hich is speci?c for that su(stance andhas a (inding site for -8P$ againstthe concentration gradient "hich re=uiresenergy0 Cells performing active transport "ill have lots of mitochondria asthey are the site of aero(ic respiration and therefore produce -8P0

DiAerences of -ctive 8ransport 4 Facilitated DiAusion 1) -ctive 8ransport uses energy2) -ctive 8ransport goes against the

concentration gradient%) -ctive 8ransport only uses carrier proteins

&o" the products of starch are a(sor(ed (y epithelial cell in small intestine lining /theseepithelial cells are +ust li!e the ones that are in the alveoli$ they have the same features)

1) Glucose moves into epithelial cell "ith sodium ion via protein2) Sodium removed from epithelial cell via carrierprotein(y activetransportinto(lood

maintaining a lo"concentrationof sodium in the epithelial cell%) Glucose moves into(lood(y facilitateddiAusion

/6pithelial cell "ill have lots of mitochondria to provide -8P for active transport of sodiumions into (lood as active transport re=uires energy as it moves against the concentrationgradient0);acteria Cells are Pro!aryotic0 -ll cells have cellsurface mem(rane0

Organelle FunctionCell 9all Physical ;arrier against mechanical damage

Capsule Protects against (acterium from other cell

&elp (acteria stic! together for protectionCell Surfaceem(rane

DiAerentially permea(le layer "hich controls the entry ande


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Diseases such as Cholera$ are due to drin!ing contaminated "ater$ therefore the highest

num(er of Cholera cases are in the summer as it is in Summer that "ater related activities

are done0

9e need lots of respiration as "e have lots of living cells and have a high meta(olic rate0


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7entilation 8he regularmovement of fresh(lood into lungs andstale air out oflungs0 ,t is helped (ythe o" of (loodaround the (ody and(lood o" removes(lood "ith higho


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') Constant concentration gradient0- tissue is a part of the (ody that contains a variety of cells0 -n organ contains a variety oftissues0

Pulmonary 8u(erculosis8ransmision Course of ,nfection 9hat it Does Cure

8ransmission airdroplets,t is caused (y (acteriacalled yco(acterium8u(erculosis0 ,t is

contagious and is found"hen people have a"ea! immune system orare living inovercro"ded conditions0/8his is "hy &,7suAerers usually get it)08he (acteria gets intoyour (ody (y (reathingin air droplets$ it canactivate years later0

8he (acteria gro" in the upperregion of lung and prosper "ithlots of o


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%) o"er diAerence in concentrationtherefore slo"er rate of diAusion

6mphysema8ransmissi

on9hat it Does Symptoms due to it

8he lungs containelastic tissue madeof the protein calledelastin0 8his tissuestretches "hen "e(reathe in and out0,n emphysema$ theelastin is

permanentlystretched0 ,t iscaused signi?cantly(y smo!ing$ (ut notentirely0

8he lungs are not a(le toforce out all the air from thealveoli0 8he surface area ofthe alveoli is reduced andalveoli (urst$ thereforecreating a(normally largealveoli0 -s a result$ little ifany gas e


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1K) 7entilation maintains concentration gradient$ therefore faster diAusion.is! measure of the pro(a(ility that damage to health "ill occur as a result of a particularha#ard0Factors 8ime Periods$ -lcohol$ Occupation$ Pollution$ Gender$ Stress$ No0 of Cigarettessmo!ed n dayFactors associated "ith cancer Smo!ing$ Diet$ Physical -ctivity$ Sunlight$ and O(esityFactors associated "ith Coronary &eart Disease /C&D) Smo!ing$ Diet$ &igh ;P$ &igh

Cholesterol$ O(esity$ and Physical -ctivity,n Graph -nalysis and Drug 8rials

1) 9hen edecrease in graph

2) Sometimes the evidence from the graph may not (e enough to dra" a certainconclusion0 9&:

-ny correlation does not mean there is a causal relationship

8here may some other factor producing a rise>fall in (oth factors

Sometimes$ there is no relation (et"een (oth factors as the graph moves along

%) Sometimes$ data is given in a logarithmic form* this e


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8he most important thing a(outthe heat structure is that "e mustloo! at the heart and consider theright and left side from the heartHspoint of vie"0 ,n other "ords$ therighthand side and lefthand side "ill (e the other "ay round0 8he left side of the heartcollects o


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%) Once 7entricle is full$ it sends do"n electrical impulse do"n ;undle of &is') 8his causes ventricles to contract

-theroma

&o" can diet increase ris! of yocardial ,nfarction

&igh salt in diet increases (lood pressure

&igh inta!e of cholesterol can result in fat accumulating under lining of artery$ this iscalled an -theroma

8his can cause a (lood clot in the coronary artery

- (lood clot prevents ocells and release to


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-ntigen olecule that stimulates an immune response$ it has a num(er of epitopes*diAerent parts of the antigen than can (e recognised as foreign (y the immunesystem and can stimulate immune response0 DiAerent antigens have diAerentnum(er of epitopes$ some can have 2$%$'$ etc0 6ach one (inds to diAerent anti(ody0

&umoral .esponse1) 8he surface antigens of invading pathogen ta!en up (y ;Cells02) ;Cells process antigenson and present them on their speci?c receptors$ if antigen

does not ?t the receptor$ then this "hole process of anti(odyproduction "ill not ta!eplace as the ;Cells "ill not (e a(le to divide0

%) 8&elper Cells attach to the processed antigens on ;Cells there(y activating them

') ;Cells$ no" activated$ divide (y mitosis to give a clone of Plasma Cells and emoryCells

P.,-.: .6SPONS6) Plasma Cells /have a large cytoplasm as it contains mitochondria for -8P and .ough

6ndoplasmic .eticulum for the production of glycoproteins) produce anti(odies thatePlasmaCells07accination Contains "ea!ened pathogen that stimulates production of anti(odies0 8his isho"

1) Contains dead>"ea!ened pathogen2) 9hen it enters the (ody$ memory cells are made


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%) On second e"ea! ,mmune System2) 8he disease may have (een contracted immediately after$ therefore not enough time

for vaccination to "or!0%) -ntigenic 7aria(ility$ the antigens from a pathogen can constantly change shape') Certain pathogens hide in the (ody) ,ndividuals may have o(+ections due to ethical issues

9hy you must give a Speci?c 7accination1) -ntigenic 7aria(ility2) No memory cells have (een made for the other types%) -nti(odies are complimentaryfor that antigen

9hy at times more than one 7accination must (e given1) ore antigens$ therefore more emory cells$ therefore more -nti(odies

9hy it may ta!e many years to see the eAect of a 7accination1) 8he disease may ta!e long to develop

2) 8he vaccination may have (een given to children "hose symptoms cannot yet (eo(served as a child

Smear 8ests may also (e carried out after the 7accination1) Disease may (e caused (y other types of antigens2) -s a precaution$ (ecause mutation may have occurred

- arge Num(er of people are 7accinated1) 7irus cannot replicate2) Non7accinated people more li!ely to contract

Doctors need to loo! at common inuen#as (efore creating 7accine1) 7accines only "or! against certain inuen#as2) 8his is (ecause each inuen#a contains diAerent antigens

%) 8herefore they can produce vaccine for the most common inuen#a

Control Group 8reated for disease "ithout active ingredients of drug0 ,nstead$ they are given

a place(o>dummy drug$ ho"ever all other treatment is the same 9&: ,S ,8

,PO.8-N8 8o see eAectiveness of drug

AQA A level Biology Unit 1 Notes

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