cell biology

Label each part of the animal cell.

Label each part of the plant cell.

Describe algal cells.

Algal cells are a lot like plant cells. They have the same organelles including a cell wall and chloroplasts

Describe fungal cells.

Fungal cells are like plant cells but there are two key differences. They do not have chloroplast and they’re cell walls are made of chitin

Describe and label the cell surface (plasma) membrane

The membrane found on the surface of animal cells and just inside the cell wall of other cells. It’s made mainly of lipids and proteins

What is the function of the cell surface (plasma) membrane.

Regulates the movement of substances into and out of the cell. It also has receptor molecules on it Which allows it to respond to chemicals like hormones

Describe and label the nucleus.

A large organelle surrounded by a nuclear envelope ( double membrane) which contains many pores. The nucleus contains chromosomes which are made from protein bound linear DNA and more structures called a nucleolus

What is the function of the nucleus?

The nucleus contains the cells activities by controlling the transcription of DNA. DNA contains instructions to make proteins. The pores allow substances (e.g RNA )to move between the nucleus and cytoplasm. The nucleolus makes ribosomes.

Describe and label the mitochondrion.

They’re usually oval shaped. They have a double membrane - the inner one is folded to form, structured called cristae. Inside is the matrix, which contains enzymes involved in respiration

What is the function of the mitochondrion?

The site of aerobic respiration, where ATP is produced. They’re found in large numbers in cells that are very active and require a lot of energy.

Describe and label the chloroplast

• a small, flattened structure surrounded by a double membrane, and also has membranes inside called thylakoid membranes.

• These membranes are stacked up in some parts of the chloroplast to form grana.

• Grana are linked together by lamellae - thin, flat pieces of thylakoid membrane.

What i# the function of the chloroplast?

The site where photosynthesis takes place. Some parts of photosynthesis happen in the grana, and other parts happen in the stroma (a thick fluid found in chloroplasts).

Describe and label the Golgi Apparatus.

A group of fluid filled, membrane bound flattened sacs. Vesicles are often seen at the edges of the sacs

What is the function of the Golgi Apparatus?

It processes and packages new lipids and proteins. It also makes lysosomes.

Describe and label the Golgi vesicle.

A small fluid filled sac in the cytoplasm, surrounded by a membrane and produced by the Golgi Apparatus.

What is the function of the Golgi vesicle

Stores lipids and proteins made by the Golgi apparatus and transport them out of the cell (via the cell surface membrane)

Describe the lysosome.

A round organelle surrounded by membrane, with no clear internal structure. It’s a type of Golgi vesicle

What is the function of the lysosome?

Contains digestive enzymes called lysosomes. These are kept separate from the cytoplasm by the surrounding membrane, and can be used to digest invading cells or to break worm out components of the cell.

Describe and label the ribosome

A very small organelle that either floats free in the cytoplasm or is attached to the rough endoplasmic reticulum. It’s made up of proteins and RNA. It’s not surrounded by a membrane

What is the function of the ribosome?

The site where proteins are made.

Describe and label the rough endoplasmic reticulum.

A system of membranes enclosing a fluid filled space. The surface is covered with ribosomes

What is the function of the rough endoplasmic reticulum?

Folds and processes proteins that have been made at the ribosomes.

Describe the smooth endoplasmic reticulum.

A system of membranes enclosing a fluid filled space.

What is the function of the smooth endoplasmic reticulum?

Synthesises and processes lipids.

Describe and label the cell wall

A rigid structure that surrounds cells in plants and algae. It’s made mainly of the carbohydrate cellulose. In fungi, it’s made of chitin.

What is the function of the cell wall?

Supports cells and prevents then from changing shape.

Describe and label the vacuole.

A membrane bound organelle found in the cytoplasm of plant cells it contains cell sap, a weak solution of sugar and salts. The surrounding membrane is called the tonoplast

What is the function of the vacuole?

Helps to maintain pressure inside the cell and keep the cell rigid. This stops plants wilting also involved in the isolation of unwanted chemicals inside the cell.

Describe the cytoplasm of a prokaryotic cell.

The cytoplasm of a prokaryotic cell has no membrane bound organelles unlike a eukaryotic cell. It has ribosomes but they’re smaller than those in a eukaryotic cell.

Describe the plasma membrane of a prokaryotic cell.

The membrane found on the surface of prokaryotic cells and just inside the cell wall of other cells. It’s made mainly of lipids and protein.

What is the function of the cell wall of a prokaryotic cell.

The cell wall supports the cell and prevents it from changing shape. It’s made of a polymer called murein. Murein is a glycoprotein (a protein with a carbohydrate attached).

Describe a capsule of a prokaryotic cell.

The capsule is made up of secreted slime.

What is the function of the capsule

It helps protect bacteria from attack by cells of the immune system.

Describe the plasmids of a prokaryotic cell.

Plasmids are small loops of DNA that aren’t part of the main circular DNA molecule.

What is the function of plasmids in prokaryotic cells?

• Plasmids contain genes for things like antibiotic resistance, and can be passed between prokaryotes.

• Plasmids are not always present in prokaryotic cells.

• Some prokaryotic cells have several

Describe how DNA is stored in a prokaryotic cell.

DNA floats free in the cytoplasm. Its circular DNA, present as one long coiled up strand. It’s not attached to any histone proteins.

Describe the flagellum of a prokaryotic cell.

The flagellum is a long, hair like structure that rotates to make the prokaryotic cell move. Not all prokaryotes have a flagellum some have more than one.

What is magnification?

The number of timed greater the size of the image is than the size of the real object

What is resolution?

The ability to distinguish between two objects that are very close together.

Describe the principles a light microscope.

• Uses light to form an image

• Light that passes through or reflects from the surface of the specimen is seen

Describe the functionality of a light microscope.

• Magnification to 2000x

• Resolution to 200nm

• Living and non living specimens can be observed

Describe the principles of a transmission electron microscope.

• Uses electrons to form an image

• Electrons that pass through the specimen are detected

Describe the functionality of a transmission electron microscope.

• Magnification to 1000,000X

• Resolution to 0.2nm

• Only dead or non living specimens can be used

Describe the principles of a scanning electron microscope.

• Uses electrons to form an image

• Electrons that are reflected from the surface on the species are detected

Describe the functionality of a scanning electron microscope.

• Magnification to 1000,000X

• Resolution to 3-20nm

• Only dead or non living specimens can be used

What an artefact?

An unnatural error, distortion, or a false signal in a study, research, or data imaging.

Give examples of artefacts that can occur during specimen or slide presentation.

• Trapped air bubbles

• Folds in thin slices of the specimen

• Chemical changes due to stains

• Contamination from other cells or tissues

What are stains used for?

Stains are used to colour different components of cells, which can give a clear indication of what substances are present in the cell, and how they are distributed.

What are the steps of cell fractionation and ultracentifugation?

1. Tissue is cut up and kept in a cold, isotonic and buffered solution

2. Cut up tissue further broken up in a homogeniser and large debris is filtered out

3. Homogenised tissue is spun in an ultracentrifuge at a low speed for 10 minutes

4. Result of being spun in ultracentrifuge at low speed

5. Spun in ultracentrifuge at medium speed

6. Spun in ultracentrifuge at high speed

   
   

What is mitosis?

a type of cell division where a parent cell divides to produce two daughter cells that have identical copies of DNA and the same number of chromosomes as the parent cell

what is meiosis?

A type of cell division where a parent cell divides to produce four daughter cells that each contain half the number of chromosomes in the parent cell

What are the stages of the cell cycle?

1. Interphase (G1, S phase, G2)

2. Nuclear division

3. Cell division

Describe the interphase.

The phase that occupies most of the cell cycle is a three step process: G1, S phase, and G2

what happens during the three steps processes of the interphase stage of the cell cycle?

• G1- gap phase: protein required for organelles are synthesised

• Synthesis phase: DNA replication takes place, resulting in a doubling of the mass of DNA

• G2- gap phase: organelles grow and divide, ATP levels increase

What happens during the nuclear division stage of the cell cycle?

The nucleus divides into two (mitosis and meiosis l) or four (meiosis ll, where each cell only contains half the chromosomes of a complete nucleus.)

What happens during the cell division stage of the cell cycle

Division of the cytoplasm known as cytokinesis, where tge cell divides into two (mitosis) or four (meiosis) new daughter cells

How long does the cell cycle take in a mammalian cell?

It typically takes 24 hours to complete

What are the stages of mitosis?

• Prophase

• Metaphase

• Anaphase

• Telophase

Describe the structural changes in the prophase?

• The chromosomes thicken and shorten by supercoiling. Each