- - The characteristics of all living things depends on the combination of traits
- They have been inherited from the organism’s parent
- this was done through ASEXUAL reproduction
- All the traits of come from 1 Parent
- Or inherited by a combination of genes from both parents
- Which is done through Sexual reproduction
- the traits come from both Parents
- *** We are going top learn later though organisms get their traits from their parent(s) their traits can be changed due to the interaction with the environment
- In the 1940’s Avery, MacLoed and Macarty found the d eoxyribo n ucleic a cid AKA DNA
- DNA is the genetic material which replicates (copies) and passes from one generation to the next
- In the 1950’s American scientist Hershey and Chase concluded that DNA controls cellular activity by helping produce enzymes
- DNA is found in the nucleus of cells
- Inside the DNA there are thousands of repeated Units called Nucleotides .
What is the purpose and function of DNA?
- DNA Structure and Function
- DNA provides the set of coded instructions required by every organism for specifying its traits.
- The DNA molecule also provides for a reliable way for parents to pass their genetic code from one generation to the next.
- Heredity refers to this passage of these instructions from one generation to another.
- Nucleotides are made out of three parts
What Exactly does DNA look like?
- DNA is a double stranded molecule which has the shape of a twisted ladder.
- This shape is called a double helix.
- The sides of this twisted ladder are composed of alternating phosphate and deoxyribose sugar units,
- while the rungs of the ladder are composed of pairs of nitrogenous bases.
- These bases are called adenine (A), thymine (T), guanine (G), and cytosine (C).
How do they connect?
- Remember the following acronym
- The A-adenine attaches to T-Thymime
- The G- guanine attaches to C-cytosine
- This principle is sometimes called complementary base
- This Model helps understand two key principles of genetics
- Genes characteristics are passed down from generation to generation by the replication of the genetic code
- Genes control cellular activity by controlling the production of enzymes (phenotype)
Where is DNA located?
- DNA is located in the nucleus
So what is the order from smallest to largest
- Hereditary information is contained in genes,
- which are composed of DNA,
- located in the chromosomes of each cell.
- Chromosomes are found in the nucleus of each cell.
- Each gene carries a separate piece of information.
- An inherited trait of an individual can be determined by one genes, but is usually determined by the interaction of many different genes.
- A single gene can influence more than one trait.
So Let us graph that out! Body Cell Nucleus Chromosome Gene DNA
- Changes in the sequence of the DNA molecule
- therefore the gene are called mutations.
- A mutation may change the manner in which a trait is expressed by an organism.