Bio 1AL Lab 5

Onion Root tips

have a region of active cell division 1-2mm from tip.

Fixative

In the root tip, must be removed or else it will repel the stain

Functions of Meiosis

1. halve the number of chromosomes 2. introduce genetic diversity via crossing over and independent assortment

S phase of interphase I

DNA replication occurs here

Meiotic prophase I

where recombination happens and crossing over, formation of tetrads.

Meiosis 1

The number of chromosomes is halved

Meiosis 2

The sister chromatids are separated

Profase 1

homologous chromosomes pair

Formula for possible gametes

2^number of chromosomes

ploidy

the number of unique and complete sets of chromosomes present on a cell NOT the number of chromosomes.

Histadine

an amino acid found in most proteins. if a cell cant make it then it cant make proteins and cant grow. it can get it from an outside source however.

his - strain

can only grow when histadine is supplemented

complementation

when a mutant allele is complemented by a wild type aleele and the gene becomes functional. two mutant strains complement each other if their two recessessive genes are different and when put together they can make every necessary protein. mutations must

yeast

can be either haploid or diploid, asexual or sexual. two haploid mating types a or ?. opposite mating types attract.

complementation test

tells you the minimum number of steps involved, not the order.

complementation group

the group of mutants that FAIL to complement one another

determining minimum number of genes

count the number of complementation groups

YPD

yeast peptone dextrose. A complete medium, one that contains all the amino acids necessary for growth, including histidine. agar is also added

SD media

synthetic defined media, one that is minimal lacking histadine.

replica plating

transferring cells from the YPD plate to the SD plate.

Prototrophs

cells that can grow on minimal media

Auxotrophs

those that require additional nutrients

Sterile velvet

tool used to transfer yeast cells from the YPD plate onto an SD plate

Vertical streak

The known mutant strain

horizontal streaks

unknown mutant strains streaked from left to right.

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