Eukaryotic Cells and Organelles Flashcards
How are plant and animal cells different?
Plant cells have all the same organelles as animal cells, with a few extras:
1. A cellulose cell wall with plasmodesmata
2. A vacuole (contains cell sap)
3. Chloroplasts
How are algae and fungal cells like plant cells?
- Algal cells are a lot like plant cells - they have all the same organelles
- Fungal cells are like plant cells with two differences - their cell wall is made of chitin, not cellulose, and they don’t have chloroplasts
Describe the structure of the cell surface membrane
The membrane found on the surface of plant and animal cells and just inside the cell wall of other cells. It’s mainly made of lipid and proteins
What is the function of the cell surface membrane?
Regulates the movement of substances in and out the cell. Has receptor molecules on it which allow it to respond to chemicals
Describe the structure of the nucleus
A large organelle surrounded by a nuclear envelope, which contains pores. The nucleus contains chromosomes and one or more structures called a nucleolus
What is the function of the nucleus?
Controls the cell’s activities (by controlling the transcription of DNA). DNA contains instructions to make proteins. The pores allow substances to move between the nucleus and the cytoplasms. The nucleolus makes ribosomes
Describe the structure of the mitochondrion
Usually oval shaped. The have a double membrane - the inner one is folded to form structures 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 the structure of a chloroplast
A small, flattened structure. It’s 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 is the function of the chloroplast?
The site where photosynthesis takes place. Some parts happen in the grana, other parts happen in the storm (a thick fluid found in the chloroplast)
Describe the structure of the Golgi apparatus
A group of fluid-filled, membrane-bound flattened sacs. Vesicles are often seen at the edges of the sac
What is the function of the Golgi apparatus?
It processes and packages new lipids and proteins. It also makes lysosomes
Describe the structure of a 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 lipid and proteins made by the Golgi apparatus and transports them out of the cell, via the cell surface membrane
Describe the structure of the lysosome
A round organelle surrounded by a membrane, with no clear internal structure
What is the function of a lysosome?
Contains digestive enzymes called lysozyme. These are kept separate from the cytoplasm by the surrounding membrane, and can be used to digest invading cells or to break down worn out components of the cell
Describe the structure of a 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 and is not surrounded by a membrane
What is the function of a ribosome?
The site where proteins are made
Describe the structure of the rough endoplasmic reticulum (RER)
A system of membranes enclosing fluid-filled space. The surface is covered in ribosomes
What is the function of the RER?
Folds and processes proteins that have been made at the ribosomes
Describe the structure of the smooth endoplasmic reticulum (SER)
A system of membranes enclosing a fluid-filled space
What is the function of the SER?
Synthesises and processes lipids
Describe the structure of the cell wall
A ridged structure that surround cells in plant, algae and fungi
What is the function of the cell wall?
Supports cells and prevents them from changing shape
Describe the structure of the cell vacuole
A membrane-bound organelle found in the cytoplasm of plant cells. It contains cell sap - a weak solution of sugars and salts. the surrounding membrane is called the tonoplast
What is the function of the cell 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
What is a tissue?
Specialised cells group together to form tissues. A tissue is a group of cells working together to preform a particular function. Different tissues work together to form organs, Different organs make up an organ system
