Genetics Vocabulary

Flow of Information from Cell to Cell 

Each cell has many double stranded pieces of DNA called chromosomes. The DNA sequence of these chromosomes are broken up into different segments that are called genes. These genes code for the amino acid sequence of a protein.   Here  are some images and definitions to help with all the vocabulary!  After you have read this over, you will have 3 chances to take the quiz. 

Chromosome

• What are they made out of?  2 strands of DNA that are complementary (match each other) 
• What information do they code for? Different stretches of the DNA sequences code for genes.
• How do you identify a specific chromosome? Chromosomes are numbered based on which genes they code for. 
• How many chromosomes does a cell have? Eukaryotes always have multiple chromosomes, each with different genes

• Shown above are the human chromosomes. You can see that they are numbered 1 through 22 and the 23rd chromosome can be either an X or Y chromosome.
• Each of those chromosomes have different genes - the black and white lines are indicating different genes on each of these different chromosomes 
• Every  human being has the gene for the receptor protein associated with hair color, and that gene is on chromosome #16. 

Homologous Chromosomes

• Humans get their chromosomes from their mother and father. This means that we have two of each chromosome. 
• ie. two chromosome #1's, two chromsome #2's , etc. 
• Here is what that looks like. ( on the right)
• Homologous is the term we use for chromosomes that have the same genes, but not necessarily the same version of each gene since we got one from one parent and the other from the other parent. 

Gene

• What are genes? These are DNA sequences that code for a specific protein's amino acid sequence
• Where are they located? Each chromosome has many genes- found in different parts of the chromosome's DNA sequences. 

Transcription: 

• This is a process of copying a section of DNA (a gene) into a type of RNA called messenger RNA
• What does this work? A series of enzymes carry out transcription. You should know the most important one: RNA Transcriptase.
• Where does this happen? In the nucleus. 

Translation

• This is the process of reading the mRNA code and translating it into the correct amino acids sequence
• What does this work? This is done by ribosomes.
• Where does this happen? In the cytoplasm.  The ribosome might move over to the R.E.R. and feed the newly forming protein into the RER space. 

Proteins

• the amino acid sequence determines the amino acid side chain interactions
• These interactions cause the folding of the protein
• The protein folding determines the shape
• The shape determines the function of the protein. 

Phenotype

• This is the appearance or function of the individual organism
• It is determined by which proteins and which version of the protein the cells make
• The term allele= a different version of the same protein. 
• Example: the version of the receptor protein that leads to black/brown hair pigments being produced, vs. the version of the receptor protein that leads to red hair pigments. 
• • Long stretches of that  DNA codes for the amino acid sequence of different proteins. 
    • These segments of DNA that code for proteins are called genes 
  • The amino acid sequence will determine the folding, shape and function of the protein
  • Those proteins determine the function of the cell and therefore of the individual.
  • The appearance and function of the individual is called their phenotype
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