Biology definitions (Unit 1)

cytosol

“broth”

jelly like substance that organelles float in

nucleus

“boss”

where DNA (instructions for building proteins) is store

-ribosomes are also made in the nucleolus

Ribosomes

“workers”

reads mRNA and links amino acids together to produce / synthesize proteins

Rough Endoplasmic Reticulum

“factory” (where ribosomes work)

manufactures proteins intended for export

Smooth Endoplasmic Reticulum

“workerless factory”

involved in the synthesis of fats, phospholipids, and steroids

Golgi apparatus

“post office”

modifies and packages proteins and lipids for exportation out of the cell

Lysosome

“recycling bin”

breaks down / digests worn down cellular components so they can be reused

mitochondria

“powerhouse”

location of aerobic cellular respiration

-breaks down glucose to produce ATP to power rest of the cell

chloroplast

“solar powered kitchen”

involved in photosynthesis

-uses sunlight to create glucose

cell membrane

“bouncer”

is selectively permeable meaning it controls what substances enter and exit the cell

Cell wall

“brick wall”

gives strength and rigidity to the cell

vacuole

“football”

stores water, nutrients and waste -also gives the cell shape

cytoskeleton

“muscles and bones”

gives cell shape and moves materials along

centriole

• made of microtubules

• involved in cell division

• only in animal cells

Cillia and Flagella

“boat oars and propella”

for cell movement

Prokaryote

• no nucleus (only nucleoid)

• circular DNA

• 
  

• eg: bacteria, archaea

Eukaryote

• has a nucleus

• has membrane bound organelles

• linear DNA (chromosomes)

• eukarya - animals, plants, fungi, protists

bulk transport

type of active transport that moves large molecules or groups of molecules across the cell membrane using vesicles

(endocytosis & exocytosis)

diffusion def

the NET passive movement of molecules across a selectively permeable membrane from an area of high concentration to an area of low concentration (along it’s concentration gradient)

osmosis def

the passive movement of free water molecules across a semi-permeable membrane from an area of low water / high solute concentration to an area of high water / low solute concentration

active transport def

the active movement of molecules across a semi-permeable membrane, from an area of low concentration to an area of high concentration (against the concentration gradient) requiring ATP

phospholipid head

• hydrophilic

• polar

phospholipid tail

• hydrophobic

• non-polar

how do prokaryotic cells generally reproduce and the steps

• Binary fission

1. DNA replication

2. elongation

3. cell division / cytokinesis

eukaryotic cell cycle

interphase (G1,S, G2), mitosis (PMAT), cytokinesis

stages of interphase

G1- cell growth

S- DNA duplication

G2- cell checks for errors and prepares for division

cell cycle checkpoints

• end of G1 - is cell big enough/enough resources?

• end of G2 - similar to G1

• towards end of Metaphase - have spindle fibres properly connected?