2 Basic components of living systems

Question 1

What is the function of the nucleus?

Answer 1

Contains coded genetic info (DNA molecules).

DNA directs synthesis of all proteins required by cell so nucleus controls metabolic activities of cell.

Question 2

What is the structure of the nucleus?

Answer 2

DNA contained within double membrane (nuclear envelope) to protect from damage in cytoplasm.
Nuclear envelope contains nuclear pores for molecules to move in and out.

Question 3

What protein does DNA associate with to form chromatin complex?

Answer 3

Histones

Question 4

What does chromatin coil and condenser to form?

Answer 4

Chromosomes

Question 5

What’s the function of the nucleolus?

Answer 5

Structure within nucleus responsible for producing ribosomes composed of proteins and RNA.

Question 6

What’s RNA used for?

Answer 6

To produce ribosomal RNA (rRNA) which combines with proteins to form ribosomes necessary for protein synthesis.

Question 7

What is the cytoskeleton?

Answer 7

Network of fibres necessary for shape and stability of cell.
Holds organelles in place and controls cell movement and movement of organelles within cells.

Question 8

What are the 3 components of the cytoskeleton?

Answer 8

Microfilaments
Microtubules
Immediate fibres

Question 9

What are microfilaments in cytoskeleton?

Answer 9

Contractile fibres formed for protein actin.

Responsible for cell movement and contraction in cytokinesis.

Question 10

What are microtubules in cytoskeleton?

Answer 10

Globular tubulin proteins polymerise to form tubes that are used to form scaffold-like structure that determines the shape of a cell.
Spindle fibres composed of microtubules.

Question 11

What are the function immediate fibres in cytoskeleton?

Answer 11

Give mechanical strength to cells and help maintain integrity.

Question 12

What are vesicles?

Answer 12

Membranous sacs that consist of a single membrane with fluid inside.

Question 13

What is the function of vesicles?

Answer 13

Storage and transport roles.

Transport- to transport materials inside cell.

Question 14

What are lysosomes?

Answer 14

Specialised forms of vesicles that contain hydrolytic enzymes (digestive enzymes) that are responsible for breaking down waste in cells (e.g. old organelles).

Question 15

What do lysosomes have an important role in?

Answer 15

Immune systems- responsible for breaking down pathogens ingest by phagocytic cells.
Also programmed cell death or apoptosis.

Question 16

What is endosymbiosis?

Answer 16

The theory that mitochondria used to be prokaryotes but then were absorbed by a eukaryote by phagocytosis and was kept rather than being digested.

Question 17

What is the structure of mitochondria?

Answer 17

Have double membrane- inner membrane is highly folded to form cristae and fluid interior (matrix)
Contain mitochondrial DNA- can produce their own enzymes and reproduce themselves.

Question 18

What is the proof for endosymbiosis?

Answer 18

Mitochondria contain 70s ribosomes, DNA (contained in plasmids) and double membrane consistent with endosymbiotic origin.

Question 19

Where does ATP generation occur?

Answer 19

Mitochondria

Question 20

What’s a fungal cell wall made from?

Answer 20

Chitin

Question 21

What are centrioles?

Answer 21

Component of cytoskeleton present in most eukaryotic cells.
Composed of microtubules.
2 associated centrioles form centrosome which is involved in assembly and organisation of spindle fibres during cell division.
Thought to play a role in positioning of flagella and cilia.