SUMMARY QUESTIONS Flashcards
List the 3 basic components of a nucleotide
- pentose (sugar)
- phosphate group
- nitrogenous (organic) base
Suggest why the base pairings of adenine with cytosine and guanine with thymine do not occur
- The bases are linked by hydrogen bonds
- the molecular structures could be such that hydrogen bonds don’t form between adenine and cytosine and between guanine and thymine
If the bases on one strand of DNA are TGGAGACT, determine the base sequence on the other strand
ACCTCTGA
If 19.9% of the base pairs inhuman DNA are guanine, calc what % of human DNA is thymine
- 30.1%
If the bases on a portion of the original strand of DNA are ATGCTACG, determine the equivalent sequence of bases on the newly formed strand
TACGATGC
Explain why the process of DNA replication is described as semi-conservative
Because half the original DNA is built into the new DNA strand
If an inhibitor of DNA polymerase were introduced into a cell, explain what the effect would be on DNA replication
- the linking together of the new nucleotides couldn’t take place
- while the nucleotides would match up to their complementary nucleotides on the original DNA strand, they wouldn’t join together to form a new strand
ATP is sometimes referred to as ‘an immediate energy source’. Explain why
- ATP releases its energy very rapidly
- this energy is released in a single step and is transferred directly to the reaction requiring it
- it is too unstable to be a long term store
Explain how ATP can make an enzyme-catalysed reaction take place more readily
- ATP provides a phosphate that can attach to another molecule, making it more reactive and so lowering its activation energy
- as enzymes work by lowering activation energy they has less ‘work’ to do and so function more readily
State 3 roles of ATP in plant cells
ANY 3 FROM:
- building up macromolecules (or named example of macromolecule)
- active transport
- secretions (formation of lysosomes)
- activation of molecules
In the following passage, state the missing word indicated by the letters a-f:
A water molecule is said to be (A) because it has a positive and negative pole as a result of the uneven distribution of (B) within it. This creates attractive forces called (C) between water molecules, causing them to stick together. This stickiness of water means that its molecules are pulled inwards at its surface. This force is called (D). Water is able to split large molecules into smaller ones by a process known as (E). Water is the raw material for the process of (F) in green plants
A - dipolar
B - electrons
C - hydrogen bonds
D - surface tension
E - hydrolysis
F - photosynthesis
