DNA, Chromosones & cell division Flashcards
(22 cards)
DNA=
DeoxyriboNucleic Acid
gene
section of DNA that codes for protein
the four bases
adenine (a)
thymine (t)
guanine (g)
cytosine (c)
complementary base
pairs are bases that match each other ie a+t and c+g
base pair rule
bases can occur in any sequence along the strand of DNA but they must be complementary
chromosones
structure found inside a nucleus of a cell
how many pairs are there
23 pairs, 46 in total
diploid cell
has two copies of each chromosomes (occurs in pairs)
haploid cell
one copy of each chromosomes
mitosis
nucleus divides into two identical nuclei that have the same number of chromosomes
functions of mitosis in multi-cellular organisams
allows for growth
replacement
and for repairs
functions in singular celled organisms
asexual reproduction ie. yeast(fungus)
cancer
develops when cells lose the ability to control the rate of mitosis
mutations
are changes in amount or structure of DNA
factors that increase the risk of cancer
^age
^hereditary (family history)
^carcinogens
-cigarette smoke
-ultra-violet radiation
- certain viral infections
-asbestos
benign tumors
non-canercous. they grow slowly and are only life-threatening if it presses against a vital organ
malignant tumors
cancerous. grow quickly and spread to other organs
how can malignant tumors be treated
through surgery, chemotherapy and radiotherapy
meiosis
(diploid cells turned into haploid cells) cells divide into 4 new cells that contain half the number of chromosomes
functions of meiosis
-produce gametes for sexual reproduction
-variation; offspring is different to parents and siblings
where does meiosis happen
animals - sex organs
plants - takes place within anthers and overies
difference between mitosis and meiosis
meiosis:
- 1 cell into 2
-new cells are identical to each other
- same # of chromosomes
mitosis:
-1 cell into 4
-not identical
-# of chromosomes is halved
