Topic 3 biology Cheat Sheet (DRAFT) by hqneyroses

An unspec­ialised cell which is differ­ent­iated and can give rise to specia­lised cells as well as divide to produce more stem cells

A cell that has the ability to differ­entiate into all cell types

A charac­ter­istic showing continuous variation caused by multiple genes at different loci

Tissue is made of one type of cell whereas an organ is made of different tissues

• tissue contains one type of cell

1. totipotent cells can { give rise to / differ­entiate to become } {any cell / extra embryonic tissues / eq }

3. idea that only totipotent cells give rise to other totipotent cells

1. stimulus / chemical / hormone

3. mRNA is translated to produce protein

1. stimulus e.g. chemical

3. transc­ription / mRNA produced at active genes

5. this protein modifies cell OR idea that this protein

1. stimulus / chemical / hormone

3. transc­ription / mRNA produced } at active genes ;

5. this protein (perma­nently) modifies cell OR idea that this protein determines { cell structure / function }

• chemical signal cause some genes to be activa­ted­/sw­itched on

• (mRNA leads to) synthesis of specific proteins which causes cell modifi­cation

• genes { activated / deacti­vated } (in stem cells)

• (there­fore) the same genes will be activated in the daughter cells

1. idea that ribosomes synthesise the { polype­ptide / protein / eq }

3. protein is folded / forms {3-D shape / secondary structure / tertiary structure }

1. in the rER insulin is folded e.g. forms {3-D shape, secondary / tertiary structure

3. vesicles { move to / fuse with / eq } the Golgi apparatus / vesicles (fuse to) form the Golgi apparatus ;

5. idea of insulin being transf­erred in (secre­tory) vesicles from the Golgi apparatus to the cell (surface) membrane ;

1. proteins are produced on the ribosomes

3. proteins are then modified in the golgi appara­tus­/body

5. proteins leave the cell by exocytosis once vesicles fuse with the cell membrane

The location of a gene on a chromsome

A disorder caused by a { mutated / faulty } gene located on the {X / Y } chromsome

• growth of organism

• repair of tissues

1. Fusion of sperm cell (membrane) with egg cell membrane

3. Contents of cortical granules react with the zona pellucida / zona pellucida {thickens / hardens }

1. idea of producing haploid { nuclei / cells }

3. Random / indepe­ndent assortment gives rise to { new / different / eq } combin­ations of (paternal and maternal) chromo­somes

5. new combin­ations of alleles produced

1. indepe­ndent assortment { of maternal and paternal chromo­somes / eq }

3. produces recomb­inants / new combin­ations of alleles / eq

1. G1 - cell grows bigger and replicates its organe­lles. A high amount of protein synthesis is taking place in order to build new organe­lles.

3. G2 - The cell keeps growing until all of the organelles have duplic­ated.

• Interphase – DNA rep / normal cell functions

• Metaphase – meet in middle / equator

• Telophase – nuclear membrane reformed – chromo­somes lengthen

• crossing over is the exchange of sections of DNA between non-sister chromatids

• same variet­y/a­ge/­length of the garlic root tip

• temper­ature

• mineral ion concen­tration

1. carefully remove the root tip from an onion that has been grown in water

3. leave the root tip in the hydroc­hloric acid for 5 minutes then take it out and place it in distilled water

5. add a cover slip on top and macerate the root tip

7. calculate the mitotic index (insert equation here)

1. removal of 5-10mm of root tips

3. add stain, e.g. toluidine (blue), orcein ;

5. place the root tip on microscope slide, covering and squashing (to separate the cells)

1. samples from different distances from the tip of the root taken

3. details of root tip squash procedure (e.g. correct use of hydroc­hloric acid, maceration procedure, squashing to produce single layer of cells)

5. squash { under a coverslip / on a microscope slide }