B13//2 Flashcards
what is base C and base T always linked to
C-G
T-A
draw a flow diagram of how protein synthesis works
what does it mean when a gene is expressed
when a gene codes for a protein that is synthesised in the cell
how can the way our genes are expressed be affected
the non coding parts of the DNA are involved in switching genes or parts of genes on and off
variations in the non coding areas may affect how are genes are expressed
what is a mutation
when new forms of genes are created as a result from changes in existing genes
what is the consequence of a few mutations
result in an altered protein that folds to give a different shape.
for example the active site of an enzyme could be changed
what is an allele
different forms of a single gene
what is a phenotype
physical appearance of the characteristic for example dimples
what is a genotype
the genetic make up which is determined by which alleles the individual inherits
what does homozygote mean
both alleles are the same
what does heterozygote mean
two alleles are different
what are the sex chromosomes for male and female
female - XX
male - XY
what is polydactyl
A genetic condition in which a baby is born with extra fingers or toes.
it is caused by a dominant allele
what is cystic fibrosis
caused by a recessive allele
it affects cell membranes and causes the production of sticky, thick mucus. the mucus can affect organs such as pancreas and lungs
what must a child inherit to get cystic fibrosis
must inherit a recessive allele from both parents
what are family trees used for
track inherited disease
show family likenesses
what is embryo screening used to do
tests to diagnose genetic disorders before the baby is born by isolating DNA
how can cells from developing fetuses be collected
amniocentesis
chorionic villus
what is amniocentesis
a sample of fluid from around the developing fetus is tested
what is chorionic villus
a sample of the placenta is tested
what does embryo screening give the parents
choices of whether to terminate the pregnancy or not
what are some concerns about embryo screening
risk of a miscarriage
information from screen tests may not be reliable
a false positive or negative
ethical issues
