click below
click below
Normal Size Small Size show me how
DNA/2
Question | Answer |
---|---|
HOW MANY ALLELE FORM EACH PARENT... | ONE.THE ALLELES MAY BE THE SAME OR DIFF. |
WHEN DIFF ALLELES ... | EACH ALLELE WILL CODE FOR A DIFF POLYPEPTIDE. RESULTING IN A DIFF SEQUENCE OF AMINO ACID. |
HENCE A DIFF PROTEIN. | |
SOMETIME THIS PROTEIN NOT FUNCTION WELL OR ... | AT ALL THE NEW SHAPE MAY NOT FIT THE ENZYMES SUBSTRATE.- AS A RESULT THE ENZYMES MAY NOT FUNCTION. |
WHY IS MEIOSIS NECCESARY ... | IN ORDER TO MAINTAIN CONSTANT NUMBER OF CHROMOSOMES THE NO ON CHROMOSOME MUST BE HALVED AT SOME STAGE IN THE LIFE CYCLE. |
DURING MEIOSIS THE CHROMOSOME PAIRS SEPARATE SO... | ONLY 1 CHROMOSOMES FROM EACH PAIR ENTERS EACH GAMETE. HAPLOID =23. |
PROCESS OF MEIOSIS ... | 1 . (MEIOSIS 1) THE HOMOLOGOUS CHORMOSOMES PAIR UP AND THE CHROMATIDS WARP AROUND EACH OTHER. BY END THE HOMOLOGOUS PAIRS HAVE SEPARATED WITH ONE CHROMOSOMES FORM EACH PAIR GOING INTO ONE OF THE 2 DAUGHTER CELLS. |
PROCESS OF MEIOSIS 2... | 2. THE CHROMATIDS MOVE APART, AT THE END 4 CELLS HAVE BEEN FORMED.- EACH WITH 23 CHROMOSOMES FOR HUMANS. |
MEOSIS BRINGS ABOUT GENETIC VARIATION BY.... | 1. INDEPENDENT SEGREGATION OF HOMOLOGOUS CHROMOSOMES, |
2. RECOMBINATION OF HOMOLOGOUS CHROMOSOMES BY CROSSING OVER. | |
LOCUS – | THE POSITION OF A GENES ON A CHROMOSOMES OR DNA MOLECULE. |
ALLELE – | ONE OF THE DIFF FORMS OF A GENE. |
INDEPENDENT SEGREGATION OF HOMOLOGOUS CHROMOSOMES IN MEIOSIS 1 | - EACH CHROMOSOME LINES UP WIT HOMOLOGOUS PARTNER. ARRANGE THEMSELVES IN LINE IT IS RANDOM. |
STAGE ½ OF MEIOSIS... | STAGE 2 : AT END OF MEIOSIS 1 : THE HOMOLOGOUS CHROMOSOMES HAVE SEGREGATED INTO 2 SEPARATE CELLS. STAGE 3: AT END OF MEIOSIS 2 – THE CHROMOSOME HAVE SEGREGATED INTO CHROMATIDS PRODUCING 4 GAMETES THE GAMETES ARE DIFFERENT. |
GENETIC RECOMBINATION BY CROSS OVER... | AFTER EACH CHROMOSOME LINES UP ALONG HOMOLOGOUS PARTNER. THEN – THE CHROMATIDS OF EACH PAIR BECOME TWISTED AROUND ONE ANOTHER. DURING THIS TWISTING PROCESS TENSIONS ARE CREATED AND PORTIONS OF THE CHORMATID BREAK OFF. |
RECOMBINATION PRODUCES... | NEW GENETIC COMBINATION ARE PRODUCED. |
IF NO RECOMBINATION BY CROSS OVER... | ONLY 2 CELLS PRODUCED BUT IF THERE IS RECOMBINATION – 4 CELLS ARE PRODUCED. |
THESE BROKEN PORTIONS THEN REJOIN WITH THE CHROMATIDS OF ITS HOMOLOGOUS PARTNER. | |
ONE OF EACH PAIR WILL PASS TO EACH DAUGHTER CELL – THIS MOVEMENT DEPENDS ON HOW THE PAIRS ARE LINED UP IN PARENT CELL. COMBINATION OF CHROMOSOMES THAT GOES INTO THE DAUGHTER CELL AT MEIOSIS 1 IS RANDOM. |