TEAS LIFE SCIENCES

Cell Theory

All life = cells

• all living things are made of cells; cells are the basic unit of life; new cells come from existing cells

Levels Of Organization

Cell → tissue → organ → system → organism

• smallest to largest

Prokaryote

NO nucleus

• simple cells (bacteria); no membrane-bound organelles

Eukaryote

TRUE nucleus

• plants, animals, fungi, protists

Cell Membrane

Gatekeeper

• controls what enters and leaves the cell

Cytoplasm

Cell jelly

• fluid where organelles are located

Nucleus

Control center

• contains DNA; directs cell activities

Ribosomes

Protein factory

• make proteins

Rough ER

R = ribosomes

• modifies and transports proteins

Smooth ER

Smooth = lipids

• makes lipids and detoxifies substances

Golgi Apparatus

Post office

• packages and ships proteins

Mitochondria

Powerhouse

• produces ATP (energy)

Lysosome

Recycle bin

• breaks down waste and old cell parts

Vacuole

Storage tank

• stores water, nutrients and waste

Chloroplast

Photosynthesis

• found only in plant cells

Cell Wall

Plant protection

• gives plants structure and support

Mitosis

Make more body cells

• produces 2 identical diploid cells for growth and repair

Meiosis

Make gametes

• produces 4 different haploid sex cells

DNA

Stores instructions

• genetic blueprint of the cell

• bases = A-T, C-G

  • adenine pairs with thymine, cytosine pairs with guanine

RNA

Reads the blueprint

• helps make proteins

• bases = A-U, C-G

  • adenine pairs with uracil, cytosine pairs with guanine

Transcription

DNA → mRNA

• copy DNA into messenger RNA

Translation

mRNA → protein

• ribosomes build protein

Gene

Instruction

• segment of DNA that codes for a trait

Chromosomes

DNA package

• carries many genes

Allele

Gene version

• different forms of same gene

Genotype

Letters