Golgi (Apparatus)
• vesicle fuses with the cis face of the Golgi
• protein undergoes modification (addition of carbohydrates or non protein element)
• protien is packaged into a secretory vesicle to be expelled from the cell
Rough endoplasmic reticulum
• RNA binds to the ribosomes (Translation)
• the polypeptide chain folds into its secondary and tertiary structure
• protein is packed into a (transport) vesicle and sent to the Golgi Apparatus
Features of the nucleus
• nuclear pore
• chromatin (intranuclear substance)
• nucleolus
• nucleoplasm
• nuclear envelop
Features of a Mitochondria
• outer mitochondrial membrane
• inner mitochondrial membrane (containing the matrix
• mitochondrial DNA inside the matrix
• transmembrane space ( space between outer and inner membrane)
Centrioles
Cylindrical structures composed of microtubules, centrioles play a crucial role in cell division by organizing the mitotic spindle.
They are typically found in pairs and are located near the nucleus in animal cells, facilitating the separation of chromosomes during mitosis.
How is sperm adapted to its function?
• Flagella (swimming)
• Mitochondria provide ATP for movement
• Acrosome contains digestive enzymes to break down zona Pellucida
• Haploid nucleus - fusing with ovum produces diploid nucleus in zygote
How is the ovum adapted to its function
• Lipid droplets provide energy for cellular divisions
• Cortical granules fuse with zona Pellucida (post-fertilisation) to alter structure and prevent polyspermy
• Haploid nucleus forms diploid nucleus with sperm in developing zygote
• Zona Pellucida secretes chemicals allowing sperm to locate ovum (chemotaxis)
• Mitochondria produce ATP for cellular divisions
PMAT
Prophase, Metaphase, Anaphase, Telophase
These are the stages of mitosis
Prophase
• Chromosomes condense and become visible (when stained)
• Chromosomes consist of two identical chromatids joined at a centromere
• Centrosomes move to opposite poles
• Spindle fibres emerge from centrosomes
• Nuclear envelope breaks into vesicles
Metaphase
• Centrosomes reach the opposite poles
• Spindle Fibres continue to extend from the centrosomes
• chromosomes line up along the equator of the spindle (making them equidistant from the poles)
• Each sister Chromatid is attached to a spindle fibre from the opposite poles)
Anaphase
• Sister Chromatids separate at the centromere
• Spindle fibres begin to shorten
• (separated) sister chromatids are pulled to opposite sides of the cell by the spindle fibres
Telophase
• New chromosomes are at the opposite ends and begin to decondense
• Nuclear envelope forms around each set of chromosomes
• Spindle fibres break down
Crossing over
This changes the alleles on different chromosomes
Independent assortment
This changes the position of chromosomes during metaphase. It means that each gamete has different chromosomes.
Stem cell
Totipotent - differentiates into all cells
Pluripotent - differentiates into most cells (not placental cells)
Multipotent - differentiates into some cells.
Methylation
Methyl groups attach to DNA and inhibit transcription of certain genes
Histone modification
Histones tighten or unwind to change the Mount of a gene that can be transcribed, it changes the amount of the gene that is transcribed.
