5 Written questions
5 Matching questions
- Spindle fibres
- Programmed cell death
- a An alternative version of a gene carrying sequence differences.
- b Structure formed on the centromere that attaches the chromosomes to the spindle fibres during mitosis and meiosis.
- c Alternative term for apoptosis.
- d A length of DNA that codes for one (or more) polypeptides/proteins. Some may code for RNA or regulate other genes.
- e Made of microtubules, these structures are responsible for providing the framework for segregation of the chromosomes during mitosis and meiosis.
5 Multiple choice questions
- The DNA strand that is used for assembly of mRNA by RNA polymerase using base-pairing rules. Complementary to the message sequence.
- Groups of homeobox genes. More complex organisms have more such groups, probably due to a mutation that duplicated them.
- A change in DNA sequence that introduces a premature stop codon within a DNA coding sequence.
- Having two sets of chromosomes (eukaryotic cell or organism). Denoted by 2n.
- A reference to the fact that normal body cells can only divide a finite number of times, normally about 50 mitotic divisions. In contrast, tumour cells are essentially immortal.
5 True/False questions
Polarity → Refers to the location of cells with respect to the head end (anterior) or tail end (posterior) of the body.
Segmentation genes → The way in which the 64 possible base triplets map onto the 20 amino acids that are used in polypeptide chains.
Meiosis → Type of nuclear division. A reduction division. The chromosome number is halved. It involves two divisions. It produces cells that are genetically different from each other and from the parent cell.
Transcription → Stage of protein/polypeptide synthesis in which the amino acids are assembled at ribosomes according to the genetic code.
transfer RNA → A short length of about 100 RNA nucleotides that adopts a clover leaf structure and carries an amino acid to the ribosome to be incorporated into a growing polypeptide chain.