Science 1.1

What Does dna stand for

 Deoxyribonucleic acid  is the carrier of genetic information

Deoxy – Means without oxygen

Ribose- A type of sugar

Nucleic Acid- A compound  of  carbon, hydrogen, oxygen, nitrogen & phosphate

Whats the purpose of DNA

 

Carries instruction to make all parts of cells and instructions to prommage how it works

WHere is DNA located and whats the DNA Molecule cstructure

 

Dna located in the nucleus of cells . It shaped ladder is called a double helix .

WHats the side of the ladder of dna called and its units

• It’s made of alternating sugar (deoxyribose) and phosphate groups.

• These units are linked by strong covalent bonds, forming a long, stable chain.

• The backbone runs along the outside of the DNA double helix.

• The nitrogenous bases (A, T, C, G) attach to the sugars and point inward.

WHats a nucloetide

In DNA, the nucleotides are the individual building blocks that make up each strand. Each nucleotide has three parts:

• A phosphate group

• A sugar (deoxyribose)

• One nitrogenous base:

What types of chemical bonds hold the DNA double helix together, and why are they important?

• Covalent bonds hold sugar‑phosphate backbone of each DNA strand.

• These bonds are strong, keeping the DNA strands stable during replication and protein synthesis.

• Hydrogen bonds connect the nitrogenous bases (A–T and C–G) in the center of the helix.

• bonds weaker, allowing the two strands to separate so the genetic code can be accessed.

Whats the complementary base pairing rule and what holds these bases together

Adenine always pairs with Thymine (A – T)

Guanine always pairs with cytosine (G – C)

The bases are held together by weak hydrogen bonds.

HOw many nitrogenous bases in DNA

4 nitrogenous base  (adenine , thymine , guanine ,  and cytosine) . 

polynucleotide vs nucleic acid

Poly nucleotide - chain of nucleotides joined together , a long polynucleotide is nucleic acid

Whats DNA molecule

• Two long strands of dna molecule made of nucleotides bonded together . Each nitrogenous base is connected to weak hydrogen bonds that form complimentary bases

QUiz what has tripple hydrogen bond

WHats a gene and how does it work

It’s a section of dna that  is a basic functonal unit of heredity ..

traits are passed down from parent to offspring .

Every human has two copies of each gene from both parents

Some genes code for protein ( basic bulidng blocks for bodies ) , how does protein help

• Repair and make new tissues

• Make much of skin , hair muscle, bone

• Make chemical messenger systems of hormones, blood and antibodies

Other genes code for a variety of molecules with different functions

WHat can genes do

Determine Genotype: Genetic code for a specific gene/ genes

--> Your genes make up you Genotype

Genome: : Your genes can also  determine  your genome  ( an organisim entire sequence of DNA ( like a set) 

Whats a alleles

 

Variations of genes that control the same trait is called alleles one of two or more alternative versions of a gene located at a specific position (locus) on a chromosom ( a variation of genes) .

 

How is genes expressed

Phenotype ; Genes are expressed through your phenotype ( how the genotype is physically expressed like eye colour  and blood type etc)

chromosome

.chromosomes  At various stage ( before cell division) It becomes tightly coiled and becomes visible  . The packed DNA is called chromosome that pass infro from parents to offspring )

they wrap dna with the double helix

How are chromosomes made

 Chromosomes form when DNA coils up and becomes visible

This happens just before the cell divides.

Pair of crhomosomes

Humans normally have 23 pairs of chromosomes ( 46 in total )

Each chromosome is made of two identitical chromatids

Chrmosome vs chromostide

• Each chromosome is made up of identical chromatids.

• The two chromatids are joined so they have long and short arms.