Plant Reproduction - Eduqas/WJEC and Edexcel B

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Eduqas/WJEC Questions

Edexcel B Questions

A level Biology Questions by Topic with Markschemes - Aerobic and Anaerobic

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Common Mistakes and misconceptions with Cells and Membranes

A few common mistakes with molecules and cells and membranes 

1. Ions are polar….. - NO - Ions are charged hence they cannot pass through the hydrophobic inside of the Cell Surface Membrane.

2. The nucleolus contains rRNA - NO - the nucleolus synthesizes rRNA (which forms part of ribosome), but it itself is made of DNA (coiled around histones)

3. Fatty acid/ hydrocarbon tails interact with hydrophobic bonds - NO Fatty acid/ hydrocarbon tails interact with hydrophobic interactions

4. Ribosomes have one membrane - NO -  Ribosomes do not have membranes

5. Facilitated diffusion uses only channel proteins. Active transport uses only carrier proteins. NO - Facilitated diffusion uses both channel proteins and carrier proteins. The carrier protein can change conformation without ATP hydrolysis. Active transport uses only carrier proteins which can change conformation only upon ATP hydrolysis

6. Exocytosis is the same as active transport - NO.- Exocytosis is a type of bulk transport requiring vesicles (and ATP to move the vesicles) , while active transport uses carrier proteins.

7. Mitochondria carry out respiration - NO - Mitochondria carry out aerobic respiration

A-level Biological Molecules - 11 basic points to help you learn

1. 99% of life is Carbon, Hydrogen, Oxygen and Nitrogen (and a bit of Phosphate)

2. Mono is one, Di (and Bi) is two, Tri is three, oligo is a few, poly is many.

3. Anything ending in -ose is a sugar, -ol is a lipid. - ase is an enzyme and all enzymes are proteins

4. Beta glucose is only in Cellulose - everything else is Alpha glucose

5. A condensation reaction makes water and joins two monomers together - glycosidic bond is a condensation reaction

6. A hydrolysis reaction breaks a bond (lysis means split) - with the addition of water (hydro)

7. A Glycosidic bond joins 2 monosaccarides together 

8. A peptide bond joins 2 amino acids together (many-poly, by peptide bonds...=polypeptide)

9. A lipid is made from a glycerol joined by an ester bond to 3 (tri) fatty acids - hence triglyceride

10. Carbohydrates and lipids are just C,H,O. Amino acids are C,H,O,N (ok, and a bit of Sulphur with 2 of the R groups), Nucleic acids (DNA, RNA, ATP) have C,H,O,N,P. Phospholipids are C,H,O,P.

11. Large or non-polar molecules are insoluble in water hence Starch, Glycogen and Fats are osmotically inactive which means they are good energy storage molecules

Learning those A-level Biology definitions with Memrise - a terrific free tool

Frequently students fail to learn the vocabulary of Biology. To get a top grade it is essential to know what the words mean in a Biological context (niche, chromosome, chromatid...), and have the confidence to use those words in an exam answer. 

I recommend using www.memrise.com, it also has iOS and android apps, there are lots of glossaries to work your way through or you can write your own. It is cleverer than it looks.

Here are a couple Eduqas component 1, Eduqas component 2