2.3 – Eukaryotic Cells Eukaryotic cells will often join with other cells to form multicellular organisms.

2.3.1 - Draw and label a diagram of the ultrastructure of a liver cell as an example of an animal cell

2.3.2 - Annotate the diagram from 2.3.1 with the functions of each named structure Nucleus - Contains the DNA of the cell, with pores in the nuclear membrane to allow movement of mRNA. Nucleolus - The location of synthesis of ribosomes for use in the cell. Rough endoplasmic reticulum - Ribosomes sit on the surface, synthesising proteins for use outside the cell. Smooth endoplasmic reticulum - Synthesises lipids and steroid hormones, as well as breaking down lipid-soluble toxins Golgi apparatus - Modifies, processes and packages macromolecules (especially proteins) into vesicles for transport within the cell

www.ibscrewed.org

Mitochondrion - The location of the reactions of aerobic respiration, providing energy for the cell in the form of ATP. Ribosomes - The free-floating ribosomes synthesise proteins that are used within the cell Cell membrane - A lipid bilayer that acts as a protective barrier for the cell. It contains chemical receptors and pores for the movement of ions and other molecules. Cytoplasm - Where the chemical reactions of life, including respiration, occur. This is mostly made up of water, but also some proteins (i.e. enzymes for metabolic reactions). Lysosomes - Membrane-bound vesicles that contain enzymes for intracellular digestion. It is important for cell defence, digesting harmful organisms and chemicals. Vacuoles - Store water to increase cell turgor.

2.3.3 - Identify structures from 2.3.1 in electron micrographs of a liver cell

www.ibscrewed.org

2.3.4 - Compare prokaryotic and eukaryotic cells Both have: 

Cell membrane



DNA



Ribosomes



Metabolism



Require energy



Cytoplasm

The differences between them are: Prokaryotes

Eukaryotes

Smaller sized cell

Larger sized cell

Cell wall

No cell wall, except in plants

Naked DNA

DNA associated with histone proteins

Contain plasmids

No plasmids

DNA in a single loop

DNA in separate chromosomes

DNA found free-floating in the

DNA enclosed in the membrane-

cytoplasm

bound nucleus

No mitochondria

Mitochondria present

Smaller, 70S ribosomes

Larger, 80S ribosomes

No membrane-bound organelles

Contains membrane-bound organelles

2.3.5 - State the three differences between plant and animal cells Plant Cells

Animal Cells

Cell wall, made up of cellulose, causing a

No cell wall

more rectangular shape Contain chloroplasts, with chlorophyll to

No chloroplasts

absorb light for photosynthesis, causing the cell to appear green Contain a large vacuole, approximately 90%

Contain significantly

of cell volume, which stores water and ions.

smaller vacuoles.

Increases cell turgor.

www.ibscrewed.org

2.3.6 - Outline two roles of extracellular components Cell Wall - This is found around all plant cells, and is composed of cellulose. It maintains the shapes of the cell and provides structural support. It also prevents the excessive uptake of water. Animal Extracellular Matrix - this is a secretion, sometimes of glycoproteins. It sits between cells, and can perform many additional functions such as support, adhesion, filtering, as well as a basis for the formation of tissue.

www.ibscrewed.org