2.1.1 Cell Structure – Cell Organelles Flashcards
(21 cards)
What is meant by the ultrastructure of a cell
The organelles found inside a cell
e.g. nucleus, mitochondria, golgi
What is the function of the nucleus?
- Nucleus controls the activities of the cell
- Contains chromatin, made of DNA, and can form into chromosomes.
What is the function of the nucleolus?
- Contains rRNA,
- Used to make ribosomes
What is the function of the nuclear envelope?
- Double membrane containing pores (gaps in between)
- that is how molecules can enter and leave the nucleus
- mRNA leaves via nuclear pore after transcription
How are chromatids formed?
- negative phosphate group of DNA combines with positive histone protein
- forms a structure called chromatin
- this is then tightly coiled
- it then forms loops
- finally becomes the chromatid of a chromosome
Draw and state the function of the rough endoplasmic reticulum (RER)?
- RER is the site of protein synthesis
- It processes the proteins once they have been made
- Rough due to ribosomes on its membrane
- Has flat sacs called cisternae
Draw and state the function of the smooth endoplasmic reticulum (SER)?
- SER is the site of lipid (e.g. fats and oils) synthesis
- It processes the lipids once they have been made
- Has flat sacs called cisternae
What is the function of the golgi apparatus (also known as the golgi body)?
- Modifies and packages proteins into vesicles
- Produces lysosomes which release digestive enzymes to destroy pathogens
- Has flat sacs called cisternae
- when drawing golgi, the cisternae must be in small to big order
Draw and state what is the function of the ribosome?
Produces proteins (protein synthesis)
- either attached to RER or free-floating in cytoplasm
- not membrane bound
- has a large subunit which tRNA attaches
- has small subunit which mRNA attaches
- bacteria have 70s (subunit) ribosomes
- plant and animal have 80s ribosomes
Draw and state what is the function of the mitochondria?
- outer membrane
- inner membrane has folds called cristae to increase surface area
- loop of DNA
- ribosomes
- matrix is the site of aerobic respiration to release ATP
Draw and state what is the function of the chloroplast?
- outer membrane
- inner membrane
- starch grain
- loop of DNA
- ribosomes
- has thylakoid which contains chlorophyll to absorb light energy for photosynthesis
- produces carbohydrates, fats and protein as end products
- stack of thylakiod called grana/granum to increase surface area
What is the function of the lysosome?
- It contains hydrolytic enzymes.
- It engulfs and digests old/dead cells and pathogens
What is the function of the cell surface membrane/plasma membrane?
It controls what enters and leaves a cell or organelle
It contains receptors for signalling molecules.
What is the function of the centrioles?
Centrioles create spindle fibres involved to separate chromosomes in cell division
What is the function of the cell wall?
It provides cells with strength, shape, structure and support.
What is the function of the cilia?
They are used to move substances outside the cell.
What are the functions of the cytoskeleton?
- Changes the shape of the cell
e.g. during phagocytosis - Supports the cell and maintains shape of cell
- Helps movement within the cell and outside of the cell
- Microtubles control the movement of organelles
e.g. Involved in movement of the cilia and flagella
e.g. Found in centrioles, that produce spindle fibres to pull chromosomes during mitosis
e.g. Assist movement of substances in cells (e.g. chromosomes during cell division or mRNA in protein synthesis) - Microfilaments
e.g. protein called actin which help muscle contraction - Intermediate fibres to give mechanical strength
Which organelle is only found in an animal cell and not in a plant cell?
Centriole
What is the function of a vacuole?
- vacuole contains cell sap of salt and sugar
- maintains turgidity (swelling and keep shape) so plant doesn’t wilt
What is the membrane of the vacuole called?
Tonoplast
Draw and name structures of a plant cell
