§5.1: Pass it on!
Your genotype is the complete set of all the characteristics you inherited from your parents. Not all of
your inherited characteristics will actually appear. For example when you tan quickly, but you’ll have
your socks on your feet will still stay pale.
Your phenotype are the set of inherited characteristics that are actually visible, this depends on both
your genotype and environmental factors, so in the circumstances in which you lived. So you can say;
phenotype = genotype + environmental factors.
Every nucleus has inside them chromosomes. Each chromosome carries a code of your inherited
characteristics. There are in total 46 chromosomes inside a fertilized egg cell.
Each chromosome has a homologous pair, this 2 chromosomes match in length and genetic
information. However, the embryo only receives one chromosome from each pair. This one
chromosome will than form with another chromosome from the other parent. Resulting that siblings
don’t look identical, because the chromosomes from the mother could match with other chromosomes
from the father the next times.
Siblings don’t have the same ancestry (the countries your ancestors came from) all the time although
they do have the same parents, this is because the parents may or may not pass this cultural
chromosomes to one child, but they do to the other child.
§5.2: What are the chances?
At females all chromosomes match, but at males the last 2 chromosomes don’t match.
One of the homologous pairs are sex chromosomes, these chromosomes determine gender. The other
22 pairs are called autosomes. There are two types of sex chromosomes: X and Y. As a boy you have
a large X and a small Y and as a girl you have two X’s. Resulting that only sperm cells can have a X
or a Y and that egg cells can only have a X, so the gender is decided by the chromosomes of the
sperm cell.
§5.3: DNA and genes
Each chromosome is made up by DNA. DNA is the
hereditary information in all your organisms, it stores,
copies and transmits information.
DNA is made up by nucleotides, this nucleotides consists
out of a sugar, phosphate and base. However, there are 4 different types of bases, guanine (G),
adenine (A), thymine (T) and cytosine (C). Base pairing is when C bonds to G and A bonds to T.
Your cells read your DNA and translate it into your inherited characteristics.
A gene is a section that has the complete code for a protein. Genes determine which type of proteins
your body makes. Proteins build cells and tissues, they have a part in determining everything like your
hair color. However, nobody has the exact same genes as you, so nobody looks exactly like you. It’s
remarkable that cells don’t read all those DNA codes, but only the ones to make proteins.