Membranes and Organelles

Prokaryotic cell

lacks a true nuclear and other membrane-enclosed organelles

where is DNA stored in a prokaryotic cell?

The nucleoid (not membrane-enclosed)

where is DNA located in eukaryotic cells

In the nucleus, bounded by a double membrane

Cytoplasm

The interior of cells: the region between the nucleus and the plasma membrane

What are plasma membranes and membranes of organelles composed of

they consist of a double layer (bilayer) of phospholipids that has many proteins attached to or embedded in it

the interior of the membrane contains..

the hydrophobic parts of the phospholipids and membrane proteins

Hydrophilic parts

are in contact with the aqueous solutions on either side

Fluid mosaic model

the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids

how is DNA carried out in Eukaryotic cells

by the ribosomes

Ribosomes

use info from the DNA to make proteins

Where does transcription happen

The Nucleus

Where does translation occur?

cytoplasm

The Nuclear envelope

encloses the nucleus, separates its contents from the cytoplasm

Nuclear pores

Regulate the entry and exit of proteins and RNAs and large complexes of macromolecules

Nucleolus

is where eRNA is synthesized

Where can free ribosomes be found?

they are in the cytosol

What are bound ribosomes attached to

The outside of the ER or nuclear envelope

What do the mitochondria and chloroplasts do

They convert energy from one form to another

Mitochondria

Site of cellular respiration (uses oxygen to extract energy from sugars, fats and other fuels)

chloroplasts

found in plants and algae, are the sites of photosynthesis, contain the green pigment (chlorophyll) and other enzymes and molecules that are in photosynthesis

The ancestors of mitochondria were . . .

oxygen using non photosynthetic prokaryotes

Ancestors of chloroplasts were

photosynthetic prokaryotes

Peroxisomes

contain enzymes that produce hydrogen peroxide, they use oxygen to break fatty acids down into smaller molecules

endomembrane system

membrane-bound organelles of eukaryotic cells are part of the ——-

Smooth ER

functions in metabolic processes: synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons, and storage of calcium ions

Rough ER

makes membrane proteins and proteins to be secreted

Glycoproteins

proteins with carbohydrates attached to them

Golgi apparatus

Shipping and receiving centre (UPS): consist of flattened membranous sacs, cistern (stack of pita bread)

Transport vesicles

Carry proteins from ER to Golgi apparatus.

Molecular Identification Tags

help in sorting by acting like postal codes on mailing labels

Lysosomes

digestive compartments: they work best in acidic environment

Exocytosis

the cell secretes certain molecules by the fusion of vesicles within the plasma membrane

Endocytosis

the cell takes in molecules and particulate matter by forming new vesicles from the plasma membrane

Phagocytosis

process of how eukaryotic cells eat by engulfing smaller organisms or food particles

how does the cell engulf its food (phagocytosis)

it extends pseudopodia around it and packages it within a food vacuole

Pinocytosis

the cell "gulps" droplets of extracellular fluid into tiny vesicles (cell drinking)

receptor-mediated endocytosis

type of pinocytosis that enables the cell to acquire bulk quantities of specific substances

Autophagy

process where lysosomes recycle the cell's own organic material

Vacoules

are large vesicles.

mature plants contain a large central vacuole