Cells (2) Flashcards
What are the 2 main groups of cells?
Eukaryote and prokaryote
What characterises a eukaryote?
Presence of a nucleus and cytoplasm containing many cell organelles
What are the 7 main eukaryotic cell organelles
Nucleus
Ribosomes
Endoplasmic reticulum
Golgi apparatus and vesicles
Lysosomes
Mitochondria and chloroplasts
What is the nucleus and it’s properties?
Contains the genetic material (linear DNA), it is bound by a double membrane called the nuclear envelope which has nuclear pores allowing communication with cytoplasm. The nucleus controls protein synthesis and thus the development and function of a cell.
What are ribosomes and their properties?
Very small organelles made up of protein and ribosomal RNA, they can be present in the cytoplasm singly or attached to the RER. They are used in protein synthesis joining AA together.
What are the 2 types of endoplasmic reticulum?
Soft and rough
What does the RER do?
Has ribosomes that produce secretory proteins which are sent to the Golgi apparatus for modification and/or packaging
What does the SER do?
Lacks ribosomes and is involved in the production and transport of lipids
What does the Golgi (apparatus) do?
Adds carbohydrates to proteins received from RER to form glycoproteins, modifying and packaging then into Golgi vesicles for secretion. This produces lysosomes (a vesicle that releases lysozymes aka hydrolytic enzymes)
What is the Golgi apparatus?
Flattened membrane sacs that are abundant in secretory cells eg in the pancreas
What are lysosomes?
Simple sacs containing hydrolytic enzymes surrounded by a single membrane these are formed by the Golgi apparatus
What are the functions of lysosomes?
1- digestion of material taken in by phagocytosis
2- digestion of engulfed non functioning organelles
3- releasing enzymes outside the cell
What is mitochondria used for?
Aerobic respiration (produces atp)
What are the functions/characteristics of mitochondria?
- bounded by 2 membranes forming an envelope around an inner matrix
- between 2 membranes is the inter membrane
- the folds of the inner membrane are called cristae
- matrix contains enzymes for respiration and DNA and ribosomes
What are the characteristics/properties of chloroplasts?
- only found in photosynthetic plant cells and algae
- within the chloroplast there is a membrane system consisting of many flattened sacs called thylakoids
- granum provides a large surface area for photosynthesis
- the stroma contains enzymes sugars and starch granules
What additional structures do eukaryotic plant cells have?
A cellulose cell wall consisting of cellulose microfibrils
Chloroplasts
A large permanent vacuole containing soluble sugars, salts and sometimes pigment
What cell wall does algae have?
Cellulose or/and glycoproteins
What cell wall does fungi have?
Chitin (polysaccharide) and a polysaccharide called glycan and glycoproteins
What is cell differentiation?
Specialised cells developed to perform specific functions, the development of cells into specialised types is cell differentiation