mitosis & tissues Flashcards
what happens during interphase in the cell cycle?
- cell grows
- DNA is copied
- protein, lipid and carbohydrate synthesis occur
- centriole replication occurs
ATP is made and used
what happens during the mitotic phase in the cell cycle?
- cytoplasm divides
- nucleus divides
why do cells undergo mitosis?
- as we grow, cells become bigger and then get to a stage where they become to large for the cell membrane transport process
- when they get to big the cells no longer function effectively
- when they get to big the cell will undergo mitosis to form two smaller daughter cells
what are labile cells?
cells that are constantly undergoing mitosis
what are stable cells?
they undergo mitosis only when some external factor indicates that they should do so
what are permanent cells?
they are amitotic - they lose the ability to undergo mitosis after a person is born
what does DNA stand for?
deoxyribonucleic acid
what does nucleotides consist of?
phosphate, deoxyribose sugar and a base
what are the sides of the DNA ladder formed by?
phosphate and deoxyribose
what bases project into the middle of the DNA ladder?
- Adenine (A)
- Thymine (T)
- Guanine (G)
- Cytosine (C)
what is cytokinesis?
splitting of the cytoplasm
what happens during prophase?
- nuclear membrane breakdown
- chromosomes form
- mitotic spindles form
what happens during metaphase?
- chromosomes line up along the middle of the cell
- mitotic spindle attaches to centromeres
what happens during anaphase?
- centromeres split and chromatids are pulled apart
- single chromosomes are pulled to either end of the cell
what happens during telophase?
- nuclear membrane forms
- mitotic spindle breaks down
- chromosomes unravel to form loose chromatin
what is a zygote?
when a male sec cell and a female sex cell join together
what must the zygote have to develop normally?
it must have 23 pairs of chromosomes = 46 in total
what is it called when a cell contains two copies of every chromosome?
diploid
what is meiosis?
a type of cell division that only occurs in the gonades
what is the definition of epithelial tissue?
a sheet of cells that covers a body surface, lines a body cavity or forms glands
what is the definition of connective tissue?
binds, supports, protects, insulates and/or transports substances within the body
what is definition of muscle tissue?
contracts to create movement of the whole body, skin or of substances within the body
what is the definition of nervous tissue?
create and transmits electrical signals allowing communication within the body
epithelia are innervated and avascular - this means what?
that they are supplied by nerve fibres, but do not contain blood vessels
what is simple squamous epithelium?
a single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm
what is the function of simple squamous epithelium?
- it allows materials to pass by diffusion and filtration in sites where protection is not important
- secretes lubricating substances in serosae (linings of ventral body cavity)