Structure of eukaryotic cells Flashcards
What is a eukaryotic cell?
Eukaryotic cells are complex cells that contain a nucleus and other membrane-bound organelles
Where are eukaryotic cells found?
In multi-cellular organisms such as animals, plants and fungi
What are the 10 key organelles in eukaryotic cells?
- Cell-surface membrane
- Nucleus
- Mitochondria
- Chloroplasts
- Golgi apparatus & golgi vesicles
- Lysosomes
- Ribosomes
- Rough ER & smooth ER
- Cell wall
- Cell vacuole
Describe the structure of the cell-surface membrane
- Phospholipid bilayer
- Molecules embedded within and attached on the outside
Describe the function of the cell-surface membrane
- Controls movement of substances in and out of the cell
- Has receptor molecules on its surface which allow it to respond to chemicals like hormones
Describe the structure of the nucleus
- Separated from cytoplasm by nuclear envelope (double membrane)
- Has nuclear pores
- Contains chromosomes: protein-bound linear DNA
- Contains one or more nucleolus
Describe the function of the nucleus
- Site of DNA replication and transcription
- Contains genetic code for each cell
Describe the function of the nucleolus in the nucleus
Synthesises ribosomes
Describe the function of the nuclear pores of the nucleus
Allows substances to move between nucleus and cytoplasm
Describe the structure of the mitochondria
- Has a double membrane
- Inner membrane folded to form cristae
- Inside inner membrane is the matrix which contains enzymes involved in respiration
Describe the function of the mitochondria
Site of aerobic respiration and ATP production
Describe the structure of a chloroplast
- Surrounded by a double membrane
- Contains fluid substance called the stroma
- Contains thylakoid membranes, which stack up to form grana
- Grana linked together by lamellae (thin, flat thylakoid membranes)
- Contains small circular DNA and ribosomes
Describe the function of a chloroplast
The site of photosynthesis
Describe the structure of the golgi apparatus
- Stack of fluid-filled membranes that make up flattened sacs called cisternae
- Contains vesicles
Describe the function of the golgi apparatus
- Modifies & packages lipids and proteins
- Produces lysosomes
Describe the function of the golgi vesicles
Transports lipids and proteins
Describe the structure of a lysosome
- Surrounded by a membrane
- Contains hydrolytic enzymes
Describe the function of a lysosome
- Releases hydrolytic enzymes called lysozymes through exocytosis
- Hydrolyses phagocytic cells
- Digests worn out organelles
- Breaks down dead cells
Describe the structure of a ribosome
- No membrane
- Consists of a large and small subunit
- Made up of proteins and rRNA (ribosomal RNA)
- Either attached to the RER or floats free in cytoplasm
Describe the function of a ribosome
- Site where proteins are made
Describe the structure of the rough endoplasmic reticulum
- System of membranes enclosing a fluid-filled space
- Surface covered in ribosomes
Describe the function of the rough endoplasmic recticulum
Processes proteins made at the ribosomes
Describe the structure of the smooth endoplasmic recticulum
System of membranes enclosing a fluid-filled space however no ribosomes
Describe the function of the smooth endoplasmic reticulum
Synthesises, stores and processes lipids & carbohydrates
