3.2.1.1 Structure of Eukaryotic Cells Flashcards
(26 cards)
What are eukaryotes?
Eukaryotes are multicellular organisms made up of eukaryotic cells like animals, plants, fungi, and protists.
What is the cell surface membrane?
- The cell surface membrane is also known as the plasma membrane.
- It is found on the surface of animal cells.
- The membrane is partially permeable
- It is mainly made up of lipids and proteins.
What is the function of the cell surface membrane?
- Controls movement of substances into and out of the cell.
- It is used for cell signalling as receptors can detect signals from other cells.
What is the structure of the nucleus?
- It contains genetic information in the form of chromosomes.
- It contains a structure known as a nucleolus.
- It is surrounded by a nuclear envelope (double membrane) containing pores.
What are the functions of the nucleus?
- It controls the cell’s activities as it contains DNA with instructions to produce proteins. (contains the genetic code for each cell)
- It is the site of DNA replication and transcription. (making mRNA)
- Synthesis of ribosomes as the nucleolus makes ribosomal RNA.
- Exchange between nucleus and cytoplasm as substances can enter or leave the nucleus via the nuclear pores.
What is the structure of mitochondria?
- Contain an enzyme-rich liquid known as the mitochondrial matrix.
- Surrounded by a double membrane in which the inner membrane is folded to form structures known as cristae.
- Contain their own DNA (mtDNA) and ribosomes.
What is the function of mitochondria?
- Site of aerobic respiration. (Produces ATP)
What are ribosomes and where are they found?
Ribosomes are very small organelles found in the cytoplasm or attached to rough endoplasmic reticulum.
What is the structure of ribosomes?
- Made up of proteins and rRNA.
- Consist of a large and a small subunit.
- ribosomes in eukaryotic cells are larger than in prokaryotic cells.
What is the function of ribosomes?
- Site of protein synthesis (Involved in the process of translation)
What is the structure of the Golgi Apparatus (Body) ?
- Contain fluid-filled, membrane-bound sacs known as cisternae.
- Contain smaller vesicles.
What is the function of the Golgi Apparatus (Body) ?
- Process and package lipids and proteins (carried out by the cisternae)
- Store and transport lipids and proteins (carried out by the vesicles)
- Synthesise lysosomes
What is the structure of the Rough endoplasmic reticulum (RER)?
- Contains a network of membranes enclosing a fluid-filled space, known as cisternae.
- The surface of the cisternae is covered with ribosomes.
What is the function of the Rough endoplasmic reticulum (RER)?
- Synthesis and transport of proteins (the proteins are made using the ribosomes)
What is the structure of the Smooth endoplasmic reticulum (SER)?
- Contains a network of membranes enclosing a fluid-filled space, known as cisternae.
- Has no ribosomes.
What is the function of the Smooth endoplasmic reticulum (SER)?
- Synthesis, storage, and transport of lipids and carbohydrates such as cholesterol and steroid hormones.
What is the structure of lysosomes?
- Lysosomes are round organelles
- They contain hydrolytic (digestive) enzymes.
- They are surrounded by a membrane to keep enzymes separate from the cytoplasm of the cell.
What is the function of lysosomes?
- Digest pathogens using enzymes.
- Break down waste material including worn out organelles and dead cells.
In addition what to plant cells contain?
- Cell wall
- Cell vacuole
- Chloroplasts
What is the structure of a cell wall (in a plant and in fungi)?
- Made up of cellulose in plants.
- Made up of chitin in fungi.
- Contains channels known as plasmodesmata.
What is the function of a cell wall?
- Supports the cell as the contents of the cell press against the cell wall to make it rigid.
- Prevents the cell from bursting as the cell wall can withstand high osmotic pressure.
- Allows exchange of substances between cells as the plasmodesmata connects neighbouring cells.
Where are chloroplasts found in plants?
Chloroplasts are found in the green parts of plants such as the leaves and stems.
What is the structure of chloroplasts?
- Contain fluid-filled sacs known as thylakoids which are stacked up to form grana.
- Surrounded by a double membrane, enclosing a fluid known as stroma which contains enzymes for photosynthesis.
- Contain their own DNA and ribosomes.
What is the function of chloroplasts?
Site of photosynthesis - These reactions take place in the grana and stroma.
