Genetic Transformationand

Protein Synthesis

Basic Unit of Life• Cells• Made of

– outside (cell membrane)– Inside (cytoplasm and organelles)

• Governed by genetic material (DNA)– DNA wrapped in a membrane = nucleus

• Characteristic of EUKARYOTIC cells (plants, animals, fungi, protists, etc)

– DNA loose in cytoplasm = nucleoid region• Characteristic of PROKARYOTIC CELLS (Bacteria)

DNA Extraction

• Virtual lab

• http://learn.genetics.utah.edu/content/labs/extraction/

Are their cells different sizes?

Cell Size

• Cells cannot grow to unlimited size

• Nucleus cannot control movement into and out of cell membrane

• Not enough of assorted organelles to get necessary work done (proteins made, waste removed, etc.)

• Key is surface area to volume ratio– A cell must have enough membrane on the

outside (ie, surface area) to control what enters and leaves the cell.

Fill in the data chart

S = width of one side

S2 = surface area of one sideX 6 = total surface area

S3 = volume

Surface area to volume ratio

Cells divide so they can maintain homeostasis.

• Requires copies of all cell contents including DNA

• DNA copies by semi-conservative replication.– Each strand is half old and half new.

• MITOSIS: Basic cell division for growth and repair.– Interphase (G1, S and G2)

– M phase:

Prophase, Metaphase, Anaphase,

and Telophase …

– followed by Cytokinesis

– Results in two “daughter” cells

Phases of the cell cycle:Phases of the cell cycle:

Plants use cell plate to separate new cells until cell wall can be made.

DNA Structure: The Double Helix

Basic unit is a nucleotide made of:

• Sugar (deoxyribose)

• Phosphate

• Nitrogenous base

• purines (double ring)

• pyrimidines (single ring)

Photo 51

DNA Replication occurs in “S” portion of Interphase.

• DNA must be copied so every new cell has the same number and same kind of chromosomes as every other cell.

• Process is

semi-conservative

Principle of Base Pairing

Adenine-Thymine

Held together by two hydrogen bonds

Cytosine-Guanine

Held together by three hydrogen bonds.

Sister chromatids

Shorter arm

Longer arm

THE STRUCTURE OF DUPLICATED CHROMOSOMES THE STRUCTURE OF DUPLICATED CHROMOSOMES AS SEEN IN METAPHASEAS SEEN IN METAPHASE

Human karyotype: n=23, 2n=46Human karyotype: n=23, 2n=46

Mutations

How is RNA different from DNA?

• Ribosomal RNA (rRNA)

• Transfer RNA (tRNA)

• Messenger RNA (mRNA)

Types of RNA

Types of RNA• Messenger RNA (mRNA) – consists of RNA nucleotides in the

form of a single uncoiled chain. – mRNA carries genetic information from the nucleus to the

cytosol. • Transfer RNA (tRNA) - consists of a single chain of about

80 RNA nucleotides folded into a hairpin shape that binds to specific amino acids. – tRNA carries amino acids from the cytoplasm to the

ribosomes. – About 45 varieties of tRNA.

• Ribosomal RNA (rRNA) - most abundant form of RNA. – rRNA consists of RNA nucleotides in a globular cluster. – Joined by proteins, rRNA makes up the ribosomes where

proteins are made.

Protein Synthesis