Flashcards in Cell Structure Deck (46)
Define the term “eukaryotic cell”
Cells with a nucleus and other membrane-bound organelles
Draw diagrams of a typical plant and animal cell, labelling the structures of the cell and annotating with their function.
Find a labelling activity online or print out a blank diagram.
Outline the structure and function of the nucleus.
- Contains coded genetic information in the form of
- Has a double membrane (nuclear envelope)
- Has pores (nuclear pores) to release RNA
- The nucleus contains chromatin which is made from DNA and proteins and often a structure called the nucleolus
- Controls cells activities and contains and instructions to make proteins
- The pores allow substances (RNA) to move between the nucleus and the cytoplasm.
1. Define the term “ultrastructure”.
The ultrastructure of a cell is those features which can be seen using an electron miscroscope
Outline the structure and function of the nucleolus
- An area within the nucleus and is responsible for the production of ribosomes.
- It is composed of proteins and RNA. RNA is used to produce ribosomal RNA (rRNA) which is then combined with proteins to make the ribosomes necessary for protein synthesis.
Outline the structure and function of the nuclear envelope.
- The nuclear envelope contains pores which allow molecules to move in and out of the nucleus.
- protects the nucleus from damage in the cytoplasm
Outline the structure and function of the rough endoplasmic reticulum.
- A system of membranes enclosing a flattened sacs called cisternae.
- The surface is covered with ribosomes.
- Fold and processes proteins that have been made at the ribosomes
Outline the structure and function of the smooth endoplasmic reticulum
- Similar to RER (A system of membranes enclosing a flattened sacs called cisternae) but no ribosomes
- Synthesizes, processes and stores lipids and carbohydrates
Outline the structure and function of the golgi apparatus.
- A group of fluid filled membrane-bound flattened sacs. Vesicles are often seen at the edges of the sacs.
- It processes, modifies and package new lipids and proteins into vesicles. It also makes lysosomes.
Outline the structure and function of the ribosomes
- Very small organelle that either floats free in the cytoplasm or is attached to the RER.
- It is made of proteins and RNA. It is not surrounded by a membrane.
- The site where proteins are made
Outline the structure and function of the mitochondria
- Usually oval shaped, has a double membrane to give a large surface area
- the inner membrane is followed to form structure called cristae
- inside is a matrix which contains enzymes involved in respiration
- the site of aerobic respiration where ATP is produced
- Found in very large numbers in cells that are very active and require a lot of energy
Outline the structure and function of the lysosomes
- a round organelle surrounded by a membrane, with no clear internal structure
- Contains hydrolytic enzymes. These are kept separate from the cytoplasm by the surrounding membrane.
- Can be used to break down invaders in the cells or break down worn out components of the cell.
Outline the structure and function of the chloroplasts.
- A small flattened structure found in plant cells.
- It is 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.
- 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 the chloroplasts)
Outline the structure and function of the plasma membrane
- The membrane found on the surface of animal cells and just inside the cell wall of plant cells and prokaryotic cells.
- It is mainly made of lipids and proteins
- Regulates the movement of substances in and out of cell. It also has receptor molecules on it, which allow it to respond to chemicals like hormones.
Outline the structure and function of the centrioles.
Small, hollow cylinders made of microtubules (tiny protein cylinders). Found in animal cells, but only some plant cells.
Involved with the separation of chromosomes during cell division.
Outline the structure and function of the cell wall
A rigid structure that surrounds plant cells. It is made mainly of carbohydrate cellulose. Fully permeable.
Supports plant cells.
Outline the structure and function of the flagella
- Flagella are like cilia but longer.
- They stick out from the cell surface and are surrounded by the plasma membrane.
- They are made of two microtubules in centre and nine pairs around the edge.
- The microtubules contract to make the flagellum move. The flagella are used like overboard motors to propel cells forward (e.g. when a sperm cell swims)
Outline the structure and function of the cilia
- small hair-like structures found on the surface membrane of some animal cells. In cross-section, they have an outer membrane and a ring of nine pairs of protein microtubules inside, with a single pair of microtubules in the middle
- The microtubules allow the cilia to move. This movement is used by the cell to move substances along the cell surface.
State 3 similarities and 3 differences between a typical plant and animal cell.
- both have a nucleus
- both have plasma membrane
- both cytoplasm
- plant cells have a lager permanent vacuole
- plants have a cell wall
- plants have chloroplasts
Draw and label a diagram of a mitochondrion.
Draw it out and check with book
Draw and label a diagram of a chloroplast.
Draw it out and check with book
Draw a diagram showing the relative sizes of different cellular components.
The nucleus, mitochondria, chloroplasts and vacuole are the biggest.
Ribosomes are very small.
Draw a flow chart that shows how different organelles and molecules are involved in the process of protein production and trafficking in a cell.
1) Nucleus - Transcription takes place. DNA is converted into mRNA and is sent out of the nucleus into the cytoplasm via the nuclear pores
2) Ribosomes - the mRNA attaches to the ribosomes on the RER and proteins are made (this is called translation)
3) Proteins are processed and folded in the RER and then they are transported from the RER to the cis face of the golgi apparatus in transport vesicles
4) At golgi apparatus proteins may undergo further processing (e.g. sugar chains are trimmed or more are added)
5) Proteins leave the golgi appartus from the transface in secretory vesicles.
6) Secretory vesicles take the finished proteins to the plasma membrane, where they undergo exocytosis and leave the cell.
Outline the structure of the 3 components of the cytoskeleton.
The cytoskeleton is a network of fibres necessary for the shape and stability of a cell.
The three components:
1) Microfilaments - contractile fibres formed from the protein actin.
2) Microtubules - globular tubulin proteins polymerise to form tubes to form a scaffold-like structure that determines the shape of a cell.
3) Intermediate fibres - these fibres give mechanical strength to the cell and help maintain their integrity.
Describe the functions of the cytoskeleton in a cell.
- The microtubules and microfilaments support the cell's organelles, keeping them in position.
- They also help to strengthen the cell and maintain its shape.
- They are responsible for the transport of organelles and materials within the cell.
- The proteins of the cell with the cytoskeleton can also cause the cell to move (e.g. the movement of cilia and flagella is caused by cytoskeletal protein filaments that run through them).
- The movement of vesicles around the cell relies on cytoskeleton proteins
Describe the importance of the cytoskeleton in movements of chromosomes
The movement of chromosomes when they separate during cell division depends on the contraction of microtubules in the spindle.
Describe the importance of the cytoskeleton in movements of cilia and flagella
The movement of cilia and flagella is caused by cytoskeletal protein filaments that run through them so in the case of single cells that have flagellum the cytoskeleton propels the whole cell (e.g sperm swimming)
Describe the importance of the cytoskeleton in movements of vesicles.
Microtubules act as tracts for the movement of organelles, including vesicles, around the cell.
Describe the importance of the cytoskeleton in the shape and behaviour of neutrophils.
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