inheritance (topic 17) Flashcards
chromosome
DNA in the nucleus of a cell is coiled and packed to form a thread-like structure,
chromosomes are made of DNA,
which contains genetic information in the form
of genes
gene
a length of DNA that codes for a
protein
dna
A large molecule made from bases, and which carries genetic information in the form of genes.
allele
An alternative version of a gene. A section of DNA that codes for a particular protein
what is the chromosome responsible for sex
XY chromsomes
xx= female
xy= male
haploid nucleus
a nucleus containing a single set of unpaired chromosomes. eg. gamete= 23 chromosomes
diploid nucleus
a nucleus containing two sets of chromosomes, for example in body cells.= 46 chromosomes (23 pairs)
how is sex inherited
each person inherits one sex chromsome from father and one from mother
sperm cell is either x or y
egg is always x
describe dna
two strands that coil together to form a double helix each strands contain complementary chemical substances called bases
T-A
C-G
genetic code
The sequence (order) of bases differs from gene to gene. The sequence of bases in a gene is its genetic code: it determines the order in which amino acids are joined together to make a specific protein
what does the sequence of bases in a gene determine
the sequence of amino acids used to
make a specific protein and different sequences of amino acids result in different shaped protein molecules
how does dna control cell function
DNA controls cell function by
controlling the production of proteins, including enzymes, membrane carriers and receptors for neurotransmitters
describe process of making proteins (protein synthesis)
-protein syntehsis occurs in ribosomes found in the cytoplasm
1. dna moelcule in nucleus unzips, exposing bases in gene
2. Mrna molecule formed using exposed bases in unzipped dna strand as template, bases in mrna bind with complementary bases in dna, mrna molecule carries a copy of the gene
3. mrna molecule moves out of the nucleus into the cytoplasm
4.ribosome reads mrna codes and joins amino acids to form protein follwoing specific base sequence in the mrna
true or false most body cells in an organism
contain the same genes, but many genes in a particular cell are not expressed because the cell only makes the specific proteins it needs
true
mitosis
nuclear division giving rise to
genetically identical cells, cells produced are called daughter cells