topic 1 Flashcards
what 7 things does a plant cell have?
nucleus cytoplasm cell membrane mitochondria rigid cell wall large vacuole chloroplasts
what what 4 characteristics does a bacteria cell have?
chromosomal DNA plasmids flagellum supported by cell wall NO NUCLEUS
what does the nucleus do?
contains DNA that controls what the cell does
what is the cytoplasm?
a gel like substance where most of the chemical reactions take place
what is the cell membrane?
holds the cell wall together and controls what goes in and out
what is the mitochondria?
where respiration takes place and energy is released
what shape is DNA
a double helix of paired bases
how are the strands held together? (DNA)
by chemicals called bases
what are the four bases?
G & C and T&A
how are base pairs joined together?
by weak hydrogen bonds
what is a gene?
a section of DNA and the sequence of bases in a gene code for a specific protein
how are proteins made?
ribosomes
how do cells make proteins?
string amino acids together in a particular order
what are three bases called?
a triplet
where is DNA found?
in the nucleus
what is transcription?
when the two DNA strands unzip and the DNA is then used as a template to make the mRNA
(base pairing ensures its complementary)
what happens after transcription?
the mRNA molecule moves out of the nucleus and joins with the ribosome
how are amino acids brought to the ribosome?
molecules called tRNA
what is the job of the ribosome?
to stick amino acids together in a chain to make a protein
what is translation?
when the mRNA molecule moves out of the nucleus and joins the ribosome where amino acids are stuck together in a chain to make a protein
how can mutations be beneficial?
produce new characteristics that is beneficial to an organisms
how can mutations be harmful?
can causes genetic disorder
what is a catalyst?
a substance that speeds up a reaction but isn’t taken up
what are enzymes?
biological catalysts produced by living things
why do enzymes have special shapes?
so that they can catalyse reactions
what four thing so ew a animal cell have?
nucleus
cytoplasm
cell membrane
mitochondria
