Biological molecules Flashcards
1
Q
Define polymers
A
Large complex molecules of long chains of monomers joined together
2
Q
Define monomers
A
Small basic molecular units
3
Q
Define condensation reaction
A
When 2 molecules join together w/ formation of chemical bond + water molecule
4
Q
Which bond forms btw 2 monosaccharides?
A
Glycosidic bond
5
Q
What makes
Sucrose?
A
Glucose + fructose
6
Q
What makes
Maltose?
A
Glucose
7
Q
What makes
Lactose?
A
Glucose + galactose
8
Q
Define hydrolysis
A
Breaks chemical bond btw monomers using water molecule
9
Q
Outline how to carry out a test for reducing sugars
A
- Add benedicts reagent to sample + heat in water bath til brought to boil
- +ve = red ppt
10
Q
Outline how to carry out a test for non-reducing sugars
A
- Add dilute HCl + heat in water bath
- Neutralise w/ sodium hydrogencarbonate
- Carry out benedict’s test
11
Q
Give examples of reducing sugars
A
- All monosaccharides
- Maltose + lactose
12
Q
Define polysaccharide
A
When more than 2 monosaccharides are joined by condensation reaction
13
Q
Outline the structure + function of starch
A
- Main energy storage in plants - excess glucose
- Mix of 2 a-glucose
- Amylose - long unbranched chain, coiled making it compact + good for storage
- Amylopectin - long branched chain, side branches allow enzymes to break down glycosidic bond easily so glucose released quickly
- Insoluble so doesn’t affect WP - doesn’t cause water to enter by osmosis
14
Q
Outline the test for starch
A
- Iodine test
- Add iodine dissolved in potassium iodide solution
- +ve = brown-orange to blue-black
15
Q
Outline the structure + function of glycogen
A
- Main energy storage in animals - excess glucose
- Polysaccharide of a-glucose
- Loads of side branches - stored glucose easily + quickly released
- Compact - good for storage
16
Q
Outline the structure + function of cellulose
A
- Major component of cell walls in plants
- Long unbranched chains of b-glucose
- Cellulose chains linked by H bonds forming strong fibres - microfibrils, provides structural support
17
Q
Outline the structure of a triglyceride
A
- 1 glycerol attached to 3 fatty acids
- FA - have long tails made of hydrocarbons, tail is hydrophobic so insoluble in water
- All FA have same basic sturcture but diff. hydrocarbon tail
18
Q
Which bond forms btw FA + glycerol?
A
Ester bond
19
Q
What are the 2 types of FA?
A
- Saturated - don’t have double bonds
- Unsaturated - have at least 1 double bond, chain kinks
20
Q
Outline the structure of a phospholipid
A
- 1 glycerol, 2 FA + 1 phopshate group
- Phosphate group = hydrophilic
- FA = hydrophobic
21
Q
Outline how the structure of triglyceride is related to its function
A
- Used as energy storage molecules
- Long hydrocarbon tails of FA contains lots of chemicial energy - loads of energy released when broken down
- Insoluble - don’t affect WP (clumps together as insoluble droplets w/ tail facing inwards)
22
Q
Outline how the structure of phospholipid is related to its function
A
- Make up bilayer of cell membrane
- Heads are hydrophilic + tail hydrophobic so form double layer w/ head facing out
- Centre of bilayer is hydrophobic so water soluble substances can’t pass through
23
Q
Outline the test for lipids
A
- Emulsion test
- Shake sample w/ ethanol for min so it dissolves then add water
- +ve = milky emulsion
24
Q
Which bond forms btw 2 aa?
A
Peptide bond
25
Describe the structure of a protein
* **1º** - **seq aa** in **polypeptide chain**
* **2º** - **H bonds** form btw aa, **coil** into **a helix** or **fold** into **b pleated sheets**
* **3º** - **Coiled** + **folds further**, **more bonds** form: **H**, **ionic** + **disulfide bridges**
* **4º** - **several diff polypeptide** joined together by bonds, forms **final 3D structure**
26
Outline the structure + function of enzymes
* **Roughly spherical** due to **tight folding** of **polypeptide** chain
* **Soluble**
* Roles in **metabolism**
27
Outline the structure + function of antibodies
* Involved in **immune system**
* Made of **2 light** polypeptide chains + **2 heavy** polypeptide chains bonded
* Have **variable regions** - **aa seq varies**
28
Outline the structure + function of transport proteins
* Contain **hydrophilic aa** causing **protein** to **fold up** + **form channels**
* **Transport molecules** + **ions across membranes**
29
Outline the structure + function of structural proteins
* **Physically strong**
* Consist of **long polypeptide chains** lying **parallel** to **each other** w/ **cross links btw**
* Include **keratin** + **collagen**
30
Outline the test for proteins
* **Biuret test**
* Solution needs to be **alkaline** so add **sodium hydroxide solution**
* Add **copper sulfate solution**
* **+ve = turns from blue to purple**
31
What is the role of an enzyme and how does it carry out its role?
* **Speeds up ROR** by **lowering** the **Ea**
* If **2 substrates** are **joining**, **attaching** to **enzyme** **holds** them **close together**, **reducing repulsions** so **bond easily**
* If **catalysing** a **breakdown**, **fitting** into **AS** puts **strain on bond** on substrate so **substrate breaks up more easily**
32
Outline the induced fit model
* As **substrate binds** the **AS changes shape slightly**
* Forming **enzyme-substrate complex**
33
What happens to the ROR when temperature is increased?
* **Inc**
* **More kinetic energy**, **molecules move faster**
* **Enzymes more likely** to **collide** w/ **substrate**
34
What happens to the ROR when temperature is too high?
* **Dec**
* Enzyme molecules **vibrate more**, **breaking** some **bonds**
* **AS changes shape** + **enzyme** + **substrate** **no longer fit**
* Enzymes **denature**
35
What happens to the ROR when the pH is too low or too high?
* **Dec**
* **H+** + **OH- mess** w/ **H** + **ionic bonds**
* Enzyme **denatures**
36
What happens to the ROR when the conc of enzymes are inc?
* **Inc** - **more likely** to **collide** w/ **substrate** **forming ES complex**
* However **no. substrate** is **limited** so **inc enzyme conc** has **no further effect**
37
What happens to the ROR when the conc of substrate inc?
* **Inc** - **more likely** to **collide** w/ enzyme **uptil point** where all **AS** are **saturated** so **inc substrate conc** has **no further effect**
* **Substrate conc dec overtime** so if **no other variables are changed**, **ROR dec over time**
38
Outline how competitive inhibitors inhibit enzyme activity
* Comp inhibitors have **similar shape** to **substrate**
* **Bind** to **AS** but **no reaction takes place**
* **Block** **AS** so **no substrate can fit**
39
Outline how non-competitive inhibitors inhibit enzyme activity
* **Bind away** from **AS**
* **AS changes shape** so **substrate** can **no longer bind**
40
Outline an experiment into measuring how fast the product of a reaction is made
* **Catalase catalyses breakdown** of **hydrogen peroxide** into **water** + **oxygen** - **oxygen displaces water** in cylinder
* Set up **boiling tube** w/ **same vol** + **conc** of **hydrogen peroxide**, add **buffer solution**
* **Boiling tube** w/ **bung** attached to **delivery tube** in **upside down measuring cyliner** in **water**
* Put each **boiling tube** in **diff temp water baths**
* **Add same vol** + **conc** of **catalase** then **attach bung**
* **Record** how much **oxygen** is **produced**
41
Outline an experiment into measuring how fast the substrate is broken down
* **Amylase catalyses breakdown** of **starch** to **maltose**
* **Drop** of **iodine** **in potassium iodide** in **well** on **spotting tile**
* **Known conc amylase** + **starch mixed** in test tube
* **Drop mixture** in **tile** at **regular intervals** + **observe colour change**
* Can see how fast amylase is working by **recording how long iodine sol no longer turns black**
* **Repeat** at **diff conc** of **amylase**
