DNA Flashcards
what does the nucleus contain?
genetic material in the form of chromosomes
what are chromosomes?
coiled up DNA molecules
what dooes chromosomes carry?
larfe number of genes,
-different genes control development of different characteristics e.h hair colour
what are body cells made up from?
2 copies of female and male chromosomes
hoow many chromosimes make up a human?
23 pairs = 46
when cells divide what is the name of this process?
mitosis
what do multicellar organisms use mitosis for?
grow or replace damaged cells
how does a cell grow and replicats DNA before mitosis?
-DNA spreads out into LONG STRINGS
-before it divides cell grows to increas amount of SUBCELLULAR STRUCTURES e.g mitochondria
-then DNA duplicates forms 2 seperate arms = X chromosomes
explain the process of mitosis?
-2 arms get pulled apart to opposite ends/poles
-membranes form around each set of chromosomes
-(becomes new nuclei)
=lastly cytoplasm & cell mebranes divides
==== produced 2 idenctical duaghter cells
(same DNA)
-
whats binary fisson?
-circulare DNA & PLASMIDS replicate
-cells gets bigger
-circular DNA strands move to opposite poles
-cytoplasm begins to divide - new cell walls form
-cytoplasm divids = 2 new daughter cells produced
from binary fission what does each daughter cell contain?
-one copy of circular DNA & various number of plasmids
how do prokaryotic cells replicate/divide?
binary fission
how often do bacteria cells divide?
mean time is 30 mins
how can u cacualate mean amount of diviosons?
-time / mean divioson time
-2 ^n of step 1