THE CELL

Animal Cell

nucleolus

chromatin

nucleoplasm

ribosomelysosomemitochondrion

cell membrane

cytoplasm

rough endoplasmic reticulum

Golgi apparatus

Golgivesicle

vacuole

centrioles

nuclear membrane

nuc

leu

s

smooth endoplasmic reticulum

Plant Cell

nucleolus

chromatin

nucleoplasm

ribosome

mitochondrion

cell membrane

cytoplasm

rough endoplasmic reticulum

vacuole

cell wallchloroplast

Structures of a CellHow many do you remember?Close all books and notes : )

nucleolus

nucleoplasm (chromosomes)nuclear pores

nuclear membrane

small vacuole

secretory vesicles

Golgi apparatus

mitochondria

smooth endoplasmic reticulumrough endoplasmic reticulum

ribosomes

cytoskeleton

cell membrane

cell wall

centrioles

large vacuole

lysosome

chloroplast

cilia / flagellum

cytoplasm

ANIMAL CELL

PLANT CELL

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nucleolus

nucleoplasm (chromosomes)

nuclear pores

nuclear membrane

small vacuole

secretory vesicles

Golgi apparatus

mitochondria

smooth endoplasmic reticulum

rough endoplasmic reticulum

ribosomes

cytoskeleton

cell membrane

cell wall

centrioles

large vacuole

lysosome

chloroplast

cilia / flagellum

cytoplasm

VIDEO

April 21, 2023 7

The Cell Membrane (also called Plasma Membrane)

The cell membrane is made up of two layers of phospholipids.

One Phospholipid Molecule• polar head (dissolve in water or soluble in water) • non polar tails (do not dissolve in water or insoluble in water) Therefore, the head is attracted to water and the tails are not attracted to water.

The Cell Membrane

Aside from phospholipids, the cell membrane also contains many other molecules such as carbohydrates and proteins.

protein channel - tunnels that allow water or specific small ions in/out of cell

Fluid Mosaic Model of the Cell Membrane

The cell membrane is a mosaic because it is made up of many pieces, just like a mosaic. It is fluid because of the phospholipid structure.

integral protein

carbohydrate

peripheral protein

phopholipid bilayer

protein channel

phospholipid

fatty acid tails

phosphate head

The Cell Membrane

The plasma membrane regulates what enters and leaves the cell.

April 21, 2023 12

General Structure of a CellCells are the basic structural and functional units of life.

Cells are bathed in an aqueous solution called extracellular fluid.

There are many different kinds of cells, which are specialized to carry out particular functions.

In spite of this, cells have many common features.

Cell Part Plant, animal or both

Function

cell membrane

•semi-permeable•controls what enters/leaves•composed of phospholipid bilayer, proteins, carbohydrates

cell wall

•tough rigid outer boundary•protection

cytoplasm • fluid that the cell organelles are suspended in

•make proteins

both

plant

ribosomes

both

both

Cell Part

Plant, animal or both

Function

smooth endoplasmic

reticulum (SER)

• canals throughout cytoplasm to transport materials• make fats

• canals with ribosomes attached (area for protein synthesis)

Golgi apparatus

• stacks of membranes which modify protein for secretion (export)• packages them into vesicles

lysosomes • contain enzymes (proteins) that can break down molecules (food, bacteria, wastes, the cell itself)

rough endoplasmic

reticulum (RER)

both

both

both

animal

Cell Part Plant, anim

or both

Function

mitochondria •powerhouse of the cell •produces energy (cellular respiration)

chloroplast • free-floating membrane-bound sac where photosynthesis occurs

• large (plants), small (animals) membrane-bound sacs filled with water• turgor pressure

vacuoles

•genetic material•contains instruction for what proteins to make

bothDNA/chromatin/chromosome

both

plant

both

Cell Part Plantanimal

or both

Function

• control centre of the cell• directs all of the cell’s activities

nuclear membrane

(1.)

• porous double membrane• separates nucleus from cytoplasm

nucleoplasm (2.)

• a mixture of chemicals that stores information• rich in nucleic acids

nucleolus (3.) • dense body in the centre of the nucleus thought to make ribosomes

both

nucleus

both

both

both

Organelles and DigestionThere are several organelles involved in the process of digestion.

Some vesicles formed in the Golgi apparatus are called lysosomes. Lysosomes are found only in animal cells. Lysosomes contain special proteins called enzymes which help them digest food by breaking it down into its building blocks. Food particles brought into the cell (through the cell membrane) from extracellular fluid may be digested this way. Potentially harmful microorganisms, such as bacteria and viruses can force themselves into a cell. Lysosomes can digest the harmful organisms so the cell is not harmed. When an animal cell gets old, lysosomes break open and decompose the entire cell. The organism then uses the resulting compounds to build new cells.

Organelles and Cellular Respiration

There is one main organelle involved in the process of cellular respiration.

Many important chemical reactions occur in the mitochondria. These reactions contribute to cellular respiration, a series of chemical changes that produce compounds that cells use as a source of energy.

Cells that require large amounts of energy, such as muscle cells in animals and root tip cells in plants, usually contain large numbers of mitochondria. Cells that do not require large amounts of energy, such as most fat cells in animals and leaf cells in plants, have smaller numbers of mitochondria.

Organelles and Protein Synthesis

There are several organelles involved in the process of protein synthesis.

Ribosomes are organelles used by the cell to produce proteins (protein synthesis). Ribosomes are either floating in the cytoplasm or attached to membranes (ER). Free-floating ribosomes produce proteins that are used inside the cell, and membrane-attached ribosomes manufacture proteins for use outside the cell. Ribosomes are so small that they appear as small fuzzy dots under the microscope.

The endoplasmic reticulum is a complicated system of membranous tubes and canals that connect with the nuclear envelope. There are two types of endoplasmic reticulum: rough endoplasmic reticulum (RER), containing attached ribosomes, and smooth endoplasmic reticulum (SER), with no ribosomes.

Because the RER contains ribosomes, many proteins are manufactured in it.

General Structure of a Cell

Homework• page 15 # 2, 3, 4, 6