2012 Unit 2 Jan Flashcards
Describe the function of a chloroplast.
- Absorbs/traps/uses light;
- For photosynthesis;
- Produces carbohydrates/sugars/ lipids/protein;
Describe what happens during anaphase that results in the production of two genetically identical cells.
- Sister chromatids
* To (opposite) poles/ends/sides;
Use your knowledge of the cell cycle to explain why some cells had 8.4 units of DNA
and others had only 4.2 units.
- 8.4/cells with twice DNA content = replicated DNA
* 4.2 = DNA not replicated
Describe how the results could show that the catfish belong to the same species.
• Fertile offspring produced;
Give two ways in which courtship increases the probability of successful mating.
- Recognises same species;
- Stimulates release of gametes;
- Recognises opposite sex;
- Indication of sexual maturity
- Formation of a bond between two organisims
Explain how this mutation leads to the formation of non-functioning PAH.
- Change in base sequence
- Change in primary structure
- Change in hydrogen bonds
- Alters tertiary structure
- Change in active site
- Substrate not complementary
- No enzyme-substrate complexes form;
Suggest how the spread of this mutation may have occurred.
- Interbreeding
* Migration
Frequent treatment with vancomycin can result in resistant strains of bacteria. Explain
how.
- Mutation present/occurs
- Resistance gene
- Resistant bacteria (survive and) reproduce
- Vertical (gene) transmission / Horizontal (gene) transmission
Use your knowledge of gene transmission to explain how the gene was passed from
one species of bacterium to another.
- Horizontal (gene) transmission
- Via conjugation/
- Plasmid/Gene/DNA replicated
- Plasmid transferred
Scientists can use protein structure to investigate the evolutionary relationships
between different species. Explain why.
• Amino acid sequences / primary structure;
• Closer the (amino acid) sequence the closer the relationship
• Protein structure) related to
(DNA) base/triplet sequence
Comparing the base sequence of genes provides more evolutionary information than
comparing the structure of proteins. Explain why.
- More bases than amino acids / longer base sequence than amino acid sequence
- Introns
- Degeneracy of code / more than one code for each amino acid
Explain the importance of taking a large number of samples at each site.
• Produces a more reliable mean/
Explain the importance of taking samples at random.
• Removes bias;
Explain the effect of developing this golf course on the index of diversity of insects.
- Increase in variety of plants/shrubs/grass
- More habitats
- Greater variety of food sources
Root pressure moves water through the xylem. Describe what causes root pressure
- Active transport by endodermis
- ions/salts into xylem;
- Lowers water potential (in xylem);
- (Water enters) by osmosis
