Show how glycerol combines with fatty acids to form a triglyceride.

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Provider: The Manchester College

Pathway: Human Biology

Diploma Title: Access to Higher Education Diploma ( Health and Physiotherapy )

Module: Biology

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Unit Title: Biological Molecules

Unit Code: GA33BIO01

Tutor/Assessor: Beth Tunstall

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Assignment Title: Biological Molecules

Type of Assignment: SAQ

Word Count:~2500 words

Time allowed for supervised assessment: NA

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Assignment Brief:
Part 1:

The first part of this unit will be assessed through the completion of a worksheet which will be done in class. The worksheet will cover assessment 1.1 and will give you an opportunity to illustrate the molecular models of simple molecules.

Part 2:

The second part of this unit will be assessed by an assignment that will cover the rest of the assessment criteria.

Q1: Complete the following table: (A.C 1.1, 1.2)

Molecule

Molecular Formula

Structural Formula

Variable

Amino Acid (Glycine R=H)

C2H5NO2

Glycerol

α-glucose

Q2. Complete the table below with a tick to show which of the following statements describe the molecules. (A.C.1.1, 1.2)

Statement

Alpha glucose

Amino acid

Fatty acid

Nucleotide

A hexose sugar

Insoluble in water

Formed by condensation
reactions

Contain the elements, C, H and O

Contains the element, N

Has a carboxyl group, -COOH

Forms polypeptides

Q3.

Show how glycerol combines with fatty acids to form a triglyceride.

Show, with the aid of appropriate diagrams, how α-glucose combines to make starch.

Name the chemical reaction that joins the glucose molecules together.

Name the bond that joins the glucose molecules together.

Explain how these polymers are digested and how the products of digestion are used in the human body.

Starch

Triglyceride

(A.C. 1.3)
Q4. Proteins are the most structurally sophisticated molecules known, consistent with their diverse range of functions, they vary extensively in structure

State the name given to the sequence of amino acids in a protein.

Name the polymer formed from a chain of amino acids.

Name the bond that is formed when two amino acids are joined together.

 

Identify the two possible outcomes of the secondary protein structure.

Identify the type of bond involved in the secondary protein structure.

Define the term ‘tertiary protein structure’.

Name the chemical bonds which serve to reinforce them and explain their role in maintaining the protein structure.

Explain why not all proteins form a quaternary structure.

 

Using an example of a globular protein and a fibrous protein relate the structure of each to their function in the human body.

Globular
Fibrous

(A.C. 2.1, 2.2, 2.3)

Q5.The structure of DNA allows it to both store and pass on information. (A.C. 3.1)
Read the following passage about the structure of DNA and chromosomes, and write the most appropriate word in each blank space to complete the account.
A DNA molecule consists of many repeating units called _________________
which are made up of _________________ sugar, a _________________, and a nitrogenous _________________. The DNA consists of _________________ strands held together by _________________bonds and the molecule is twisted into a __________________________________. There are four different nitrogenous _________________ They are _________________, _________________, _________________ and _________________A gene is a section of DNA that codes for the production of a _________________.The molecule that copies a gene is called a __________________________________.
Q6.DNA and RNA are nucleic acids. The table below contains a number of statements relating to nucleic acids.

Complete the table, using a letter D, R or B, to show whether each statement applies to:

DNA only (D)
RNA only (R)
Both DNA and RNA (B)

Statement

D or R or B

Contains thymine

Contains ribose

Consists of two chains connected to each other with hydrogen bonds

Has a sugar-phosphate backbone

Has four different nitrogenous bases

Contains a pentose sugar

Is found in the nucleus and cytoplasm

(b) Explain why DNA is structurally stable.
(c) Usetheimagebelowtocompletethefollowing:
Circleanucleotide.
Labelthesugarandphosphate.
Labelthebasesthatarenotalreadylabelled.
(d)WritethecomplementarysequencetofollowingDNAstrand:
A A T T C G C C G G T A T T A G A C G T T
| | | | | | | | | | | | | | | | | | | | |
Q7. Meselson and Stahl conducted an experiment to prove that the replication of DNA is semi-conservative. (A.C. 3.2, 3.3,)

Replication of DNA is described as ‘semi-conservative’. Explain this term.
Explain how the DNA molecule replicates.
Meselson and Stahl’s experiments involved growing bacteria in culture media containing either heavy nitrogen (15N) or light nitrogen (14N). The DNA was then extracted from the bacteria.

The table below summarises the three stages of Meselson and Stahl’s experiment and their results.

Complete the table by drawing, in the appropriate boxes, diagrams of the DNA molecules and mark the position and size of the DNA bands in the tubes.

Experimental stage

Diagram to show the strands in the DNA molecules of the bacteria

Position and size of DNA bands in the tube of separating solution

Stage 1
Bacteria grown for several generations in culture medium containing heavy nitrogen

Stage 2
The bacteria from the end of stage 1 were grown for another generation in culture medium containing light nitrogen

Stage 3
The bacteria from the end of stage 2 were grown for one more generation in culture medium containing light nitrogen

The bacteria at the end of stage two were grown for five more generations. After each generation, what would you expect to see in the test tube? Draw these in the test tubes below.

Gen. 0

Gen. 1

Gen. 2

Gen.3

Gen.4

Which part of the DNA molecule would be expected to incorporate the nitrogen?

Q8. Protein synthesis is carried out by the processes of transcription and translation.
A short length of DNA is shown:
TACTCGTCGACGATGATC

State how many codons are present.

(b) Using the table below, find the sequence of amino acids resulting from the transcription and translation of the length of DNA. Show your working.

Grading Information for this Assignment

Grade Descriptor: 1: Understanding the Subject

For a Merit your work or performance must: demonstrate a very good grasp of the
relevant knowledge base

For a Distinction your work or performance must: demonstrate an excellent grasp of the
relevant knowledge base

Learner Guidance notes:
You should explain the information clearly and simply to show a higher level of understanding.

Grade Descriptor: 2: Application of Knowledge

For a Merit your work must : make use of relevantfacts with breadth or depth that goes beyond the minimum required to passand brings together information with very good levels ofsynthesis

For a Distinction your work must: make use of relevantfacts with breadth or depth that goes beyond the minimum required for merit and with excellent levels ofsynthesis.

Guidance notes:You should bring together information throughout the assignment. You will show higher levels of synthesis in the work.

Grade Descriptor: 5: Communication and Presentation

For a Merit your work or performance must show very good command of format, structure, language (including technical orspecialist language), spelling, punctuation, and referencing.

For a Distinction your work or performance must showexcellent command of format, structure, language (including technical orspecialist language), spelling, punctuation, and referencing.

Guidance notes: You should get into the habit of proof reading your work. Once you have completed your final draft, proof read the work for mistakes. Ensure that you have used HARVARD REFERENCING FORMAT for the assignment as requested in the assignment brief.

Grade Descriptor: 7 Quality

For a Merit your work or performance must: be structured in a way that is generally logical and fluent and puts forward arguments or ideas which are generally unambiguous but which are in a minor way limited or incomplete.

For a Distinction your work or performance must: be structured in a way that is consistently logical and fluent and puts forward arguments or ideas which are consistently unambiguous and cogent.

Guidance notes: You should aim to present the work in a way that shows a clear ‘story’ through the information you supply. Your information should make sense throughout. Proof read the work in order to ensure that all of the quality aspects are covered.

No.

Assessment Criteria
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First Submission

Second Submission

Referral

1.1

Illustrate or construct molecular models of simple organic compounds.

1.2

Distinguish between the structural and molecular formulae of α-glucose, an amino acid, glycerol, a fatty acid and a nucleotide.

1.3

Show how small biological molecules combine to form larger molecules yielding water.

2.1

Describe the levels of structure in proteins.

2.2

Explain the roles of hydrogen and ionic and covalent bonding in maintaining protein structures.

2.3

Relate the uses of globular and fibrous proteins to their structures.

3.1

Describe the levels of structure in DNA and explain why DNA molecules are so stable.

3.2

Explain how the self-replicating ability of the DNA molecule is related to its structure.

3.3

Explain data showing that the replication of DNA is semi-conservative.

3.4

Interpret data to find the sequence of amino acids resulting from the transcription of a short length of DNA (minimum 15 bases).

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