Bio 30 Diploma: cell division, genetics and molecular biology Exam

Normal human chromosome number is ? - ANS 46 Mitosis occurs? - ANS When an organism grows or needs to repair itself. The period from one cell division to the next is called a cell cycle and is divided into three stages called? - ANS Interphase mitosis and cytokinesis. Interphase can be divided into three phases. Which are? - ANS G1, S and G2 What makes up one chromosome? - ANS Two sister chromatids joined by a centromere In anaphase the centromeres divide so each sister chromatid had it's own centromere (how does this effect what we call the sister chromatids?) - ANS Because the definition of a chromosome is any DNA held together by a centromere, each sister chromatid is now it's own chromosome Alternation of generations is a? Used? - ANS Alternation of generations is a reproductive strategy employed by plants to maximize reproduction. Plants have two different multicellular forms: - ANS A diploid form called a sporophyte, and a haploid form called a gametophyte See pic on page 80 of the key!!!!! - ANS ... Phenotype vs genotype? - ANS Phenotype: is used to describe an observable trait Genotype referees to the alleles present in each individual. Incomplete dominance? - ANS If both alleles are present in the genotype, and neither is dominant, then the phenotype will be a mixture of the two Polygenic - ANS Two or more genes determine a single trait Epistatic - ANS Meaning that two genes interact to form different phenotypes In pedigrees males are? Females are? - ANS Males are squares Females are circles A father will pass? - ANS His X Chromosome to his daughter His Y chromosome is always passed on to his sons A condition is autosomal recessive if? - ANS Unaffected parents are producing an affected child (skips generations) If significantly more males than females have the condition then the condition is probably? - ANS X-linked recessive If significantly more females than females have the condition then the condition is probably? - ANS X-linked dominant when two genes are linked then what cannot occur? - ANS when two genes are linked on the same chromosome, then independent assortment cannot occur because the linked alleles are not free to separates from each other. AaBb• AaBb should produce that phenotypic ratio? - ANS 9:3:3:1 The percentage of crossover is related to? - ANS The distance between two genes on a chromosome. The farther away the two genes are from each other the greater the probability of a cross over event. And the higher the number of recombinant offspring that would occur. Cross over percentage = - ANS (number of recombinants/total number of offspring ) • 100% Chargaff discovered ? - ANS the relationship between the amounts oof nitrogen bases in a molecule of DNA. DNA has a double helix structure made of ? - ANS Two strings of nucleotides joined in the middle by hydrogen bonds. A nucleotide consist of? - ANS - a deoxyribose sugar, a phosphate group, and a nitrogen base attached to the sugar Base pairing? - ANS The purine nitrogen bases adenine always pairs with the pyrimidine thymine (T), and the purine guanine (G) always pairs with the pyridine cytosine (C). Helicase? - ANS Unzips the double helix of DNA by breaking hydrogen bonds between the base pairs Each template strand is joined to? Making? - ANS Each template strand is joined to it's complementary strand with hydrogen bonds forming two identical DNA molecules 3 difference between DNA and RNA - ANS 1. The sugar in RNA is ribose, not deoxyribose 2. RNA has the base uracil in place of the DNA base thymine. 3. RNA is single stranded mRNA and tRNA - ANS mRNA- messenger RNA will function to make a copy of the DNA in the nucleus and bring it to the ribosome in the cytoplasm. Transfer RNA (tRNA) will function to pick up requested amino acids from the cytoplasm and bring them to the ribosome for the assembly Protein synthesis is divided into two phases? - ANS Transcription and translation In transcription? Occurs where? - ANS In transcription, which occurs in the nucleus, the base sequence on the DNA is copied complementary onto a molecule of messenger RNA Use of codon translation table - ANS The ribosome determines which amino acid that particular codon is requesting. Table is mRNA codon tRNA molecules - ANS One end of the tRNA molecule has an anticodon that complementarily matches the codon on the mRNA currently being read by the ribosome. The other end of the tRNA is attached to the requested amino acid. Restriction enzymes are used in recombinant DNA technology how? - ANS Restriction enzymes are used in recombinant DNA technology, acing as chemical scissors that are used to cut DNA. Each type of restriction enzyme recognizes a specific DNA sequence and cuts at this recognition site in a precise way producing gene segments that have sticky ends made if a sequence of unpaired bases.