voice of the genome Flashcards
how is DNA organised in a bacterial cell?
- large circular DNA
*DNA not associated with histone proteins - several small plasmids
- located in the cytoplasm
what are the roles of the Golgi apparatus and vesicles in the formation and transport of extracellular enzymes?
- vesicles fuse w Golgi apparatus
- modification of proteins inside Golgi apparatus
- protein packaged into secretory vesicles
- vesicles fuse w cell surface membrane
what happens to lysosomes once their contents have been digested?
- lysosome fuses w cell surface membrane
- contents of lysosome released from cell/ exocytosis
how can eukaryotic organisms be differentiated from prokaryotic?
- membrane bound organelles
- mitochondria, RER, SER, nucleus, Golgi, vesicles
- larger ribosomes
- linear DNA associated w histone proteins
- no plasmids in cytoplasm
how can prokaryotic cells be identifies?
- circular DNA/ plasmids
- 70s ribosomes
- pili/ flagellum
- capsule/ mesosome
why can the nucleus not be observed at the end of prophase?
- nuclear membrane is broken down
- DNA is coiled and condensed into individual chromosomes
what are the functions of the Golgi apparatus?
- modifies proteins
- forms vesicles
- removes some water from the protein
where does protein synthesis occur in eukaryotic cells?
80s ribosomes on the endoplasmic reticulum
where is the capsule located in some bacteria?
outside the cell wall
what is the function of plasmodesma?
- cytoplasmic connection between cells
- which allows transport/ communication between cells
why is HCl added to the root tip when observing cell division?
- breaks down middle lamella
- allowing cells to be separated
- to allow light to pass through
why is a stain added to the root tip when observing mitosis?
- makes the chromosomes visible
- so that the stages of mitosis can be identified
how does the shortening of spindle fibres affect mitosis?
- sister chromatids cannot be separated
- anaphase cannot occur
- daughter cells produced with incorrect numbers of chromosomes
what are the events of fertilisation that occur after the acrosome reaction?
- fusion of sperm cell w egg cell membrane
- cortical granules release contents into zone pellucida
- contents of cortical granules react w zoned pellucida
- zona pellucida hardens
- fusion of sperm and egg nuclei
why may offspring be genetically different?
- each zygote is formed from different gametes
- each gamete contains different combinations of alleles
- due to independent assortment/ crossing over