Edexcel A level biology Study guides, Class notes & Summaries

monosaccharides - Answer single simple sugar molecule disaccharides - Answer sugar made up off two monosaccharide units joined by a glycosidic bond formed in a condensation reaction polysaccharides - Answer polymer made up of long chains of monosaccharide units joined by glycosidic bonds condensation reaction - Answer reaction in which a molecule of water is removed from the reacting molecules as a bond is formed between them glycosidic bond - Answer covalent bond form...

Molecular phylogeny - Answer It compares the structure of a particular molecule from different organisms to discover their degree of evolutionary relation. Somatic cell - Answer A cell in an organism which isn't a gamete. DNA - Answer Deoxyribose nucleic acid. Carries the genetic information for cells and some viruses. mRNA - Answer Messenger ribose nucleic acid (single stranded). The product of transcription. Speciation - Answer The process through which a species is...

Describe what is meant by biodiversity. (2) - Answer Variety of species in an ecosystem and the variety of alleles in a gene pool. Explain how the biodiversity of lemurs in two different parts of Madagascar could be compared. (3) - Answer Record total number of species of lemur and total individuals within each species. Calculate an index of diversity for each location. The higher the index of diversity the greater biodiversity. gel electrophoresis/ dna profiling/molecular phylogeny/ p...

What is a nucleotide? - Answer Nitrogen base + sugar (ribose or deoxyribose) and phosphate group joined by a condensation reaction with TWO water molecules released. What is the role of a nucleotide? - Answer - provide the building blocks for the mechanism of inheritance in the form of DNA and RNA. What are the pentose sugars in DNA and RNA and what is the difference between the two. - Answer DNA = deoxyribose RNA = ribose Deoxyribose contains one fewer oxygen atoms than ribose ...

What is the purpose of having a heart and circulation? - Answer Moving substances around the body Why do larger organisms need a mass transport system, not an open circulatory system? - Answer Larger diffusion distances: slower transport of substances Why is water a good transport medium? (3 things) - Answer Dipole, solvent, thermal properties What is meant by a dipole molecule? - Answer One end is slightly positive and one end is slightly negative. Why is the dipole natu...

Describe the events of fertilisation that occur after the acrosome reaction. - Answer -Membrane of sperm and egg cell fuse together -cortical granules release contents into zona pellucida -Zona pellucida thickens -Haploid nuclei fuse Explain how phospholipids form a cell surface membrane - Answer -Hydrophilic parts associate with water -Hydrophobic parts repel water -a bilayer forms with hydrophobic parts pointing in towards the centre of the bilayer Describe the role of the ...

Topic 1 - Answer Biological Molecules Name the type of chemical reaction that joins monosaccharides together to form an amylose molecule. - Answer condensation reaction Describe the meaning of the term hydrolysis. - Answer breaks bonds via the addition of water Describe one structural difference between amylose and glycogen. - Answer Glycogen is highly branched with both 1,4 and 1,6 bonds whereas amylose is a straight chain with only 1,4 bonds. Name the chemical bond that...

A sequence of changes in a community Over a period of time - Answer Define Succession Final stage Stable - Answer Define Climax community Thylakoids made of membranes Arranged as grana Contain chlorophyll Arranged as photosystems Membranes contain ATPase Electron carriers associated with thylakoid membranes - Answer Describe the structures in a chloroplast involved in the light-dependent reactions Crops grown all year round Plants photosynthesise 24 hours a day Less physi...

Edexcel A-level biology exam questions and answers 100% pass Describe the events of fertilisation that occur after the acrosome reaction. - Answer-- Membrane of sperm and egg cell fuse together -cortical granules release contents into zona pellucida -Zona pellucida thickens -Haploid nuclei fuse Explain how phospholipids form a cell surface membrane - Answer--Hydrophilic parts associate with water -Hydrophobic parts repel water -a bilayer forms with hydrophobic parts pointing in towards...

Edexcel a level biology topic 4 exam questions and answer Describe what is meant by biodiversity. (2) - Answer-Variety of species in an ecosystem and the variety of alleles in a gene pool. Explain how the biodiversity of lemurs in two different parts of Madagascar could be compared. (3) - Answer-Record total number of species of lemur and total individuals within each species. Calculate an index of diversity for each location. The higher the index of diversity the greater biodiversity. ...