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33 Cards in this Set
- Front
- Back
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Define a species |
Capable of breeding to produce live and fertile offspring. |
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State the rules and of a binomial system |
Universal system based on Latin or Greek The first name is generic (denotes genus organism belongs) Second name (specific name) - where species belong Names shpuld be written in Italics or handwritten names should be underlined |
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Define classification |
Arrangement of organisms into groups of a variety of sizes and on the basis of shared features |
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Define taxonomy |
Form of classification focused on physical similarities between species. There is ease in naming and identification |
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Define the term phylogeny |
Classification of organisms by evolutionary relationships so every group shares common ancestor |
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State the hierarchy for classification |
Domain Kingdom Phylum Class Order Family Genus Species |
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Define the term nomenclature |
System of naming things |
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Describe the steps of transcription |
DNA double helix would be unwound near start of gene and weak hydrogen bonds between bases are broken
Enzyme RNA polymerase makes complementary RNA copy of one DNA strand.
End product is pre-mRNA |
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State step 1 in transcription |
RNA polymerase attaches to DNA double helix at beginning of the gene. H-bonds break between two DNA strands, break and seperate strands. DNA molecule uncoils exposing some bases. One of the strands is used as a template to make an mRNA copy |
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(Example question and recall) Aspartic acid and proline are both amino acids. Describe how two amino acids differ from one another. |
They would have a different R group |
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(Mutations) Why would deletion affect the nature of the protein compared to substitution? |
Deletion causes frame shift, changes the base sequence. Substitution doesn't because of its base sequences' degenerate nature (codes for more than one amino acid) |
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Step 1 for transcription |
Enzyme acts on specific region of DNA causing two strands to seperate Expose nucleotide bases in that region |
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Step 2 of transcription |
Nucleotide bases on one of two DNA strands (template strand) pairs with complementary nucleotides from the pool present in nucleus RNA polymerase moves along strand and joins nucleotides together to form pre-mRNA molecule |
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State step 3 of transcription |
In this way, exposed guanine base on DNA binds to cytosine base of a free nucleotide Cytosine links to guanine and thymine joins to adenine |
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State step 4 of transcription |
RNA polymerase adds nucleotides one at a time build a strand of pre-mRNA. DNA strands rejoin behind it Only about 12 base pairs on DNA exposed at any one time |
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State step 5 of transcription |
RNA polymerase reaches particular sequence of bases on DNA which recognises a STOP codon Detaches and production of pre-mRNA is complete |
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What is meant by 'degenerate code'? |
Codes for more than one triplet. |
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(Cell Cycle) Name the phase during which DNA Replication occurs. |
Interphase |
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State the stages of the cell cycle in mitosis |
Interphase Prophase Metaphase Anaphase Telephaae |
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Briefly state the stage prophase |
Chromosomes condense, getting shorter and fatter Centrioles start moving to opposite ends of the cell forming a spindle Nuclear envelope breaks down and chromosomes lie free in the cytoplasm |
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State what occurs in metaphase |
Chromosomes (each with two chromatic) line up on the spindle equator and become attached to the spindle by their centromere |
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State what occurs in anaphase |
Centromere divide, each pair of sister chromatids separate. Spindles contract, chromatids pulled to opposite poles of the spindle. Centromeres first making chromatids appear v-shaped |
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State what occurs in telophase |
Chromatids reach opposite poles on spindle Uncoil and become long and thin again. Now are chromosomes again Nuclear envelope forms around each group of chromosomes so there are now two nuclei |
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What is meant by an allele? |
One of a number of alternative forms of a gene |
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What does mitosis produce? |
Two daughter cells with same number of chromosomes as parent cell and as each other |
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What does meiosis produce? |
Produces four daughter cells, each with half number of chromosomes as parent cell |
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State the first nuclear division (meiosis 1) |
Homologous chromosomes pair up and chromatids wrap around each other. Equivalent portions of chromatids exchanged in process crossing over By the end of this division homologous pairs separated with one chromosome from each pair going into one of two daughter cells |
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State second meiotic division (meiosis 2) occurrences |
Chromatids move apart, at the end of meiosis 2. At end of meiosis 2, four cells have usually been formed |
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Why are lipids useful as storage molecules? |
Don't dissolve in water, therefore, don't affect osmotic balance of cells have higher calorific value than carbohydrates can yield more energy per gramme oxidation |
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In what ways do the properties of saturated and unsaturated fats differ? |
Saturated fats are solid and unsaturated fats form oils. Unsaturated fats have lower m.p. than saturated fats |
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In what way would the structure of a phospholipid differ from this triglyceride? |
One fatty acid molecule replaced by phosphate molecules |
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'Amino acids are amphoteric.' What does this mean? |
Their molecules contains both acidic and basic group |
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State how structural differences between starch and cellulose |
Starch contains a-glucose only and cellulose b-glucose only. Cellulose is unbranched and starch is branched |
