Cell Structure and Organsisation

Question 1

What is the function of the nucleus?

Answer 1

It retains the genetic information (DNA) which codes for protein synthesis

Question 2

What is the nuclear envelope and its function?

Answer 2

A double membrane with pores to allow the transport of mRNA and ribosomes out of the nucleus

Question 3

What is the function of the nucleolus?

Answer 3

To synthesise ribosomal RNA (rRNA)

Question 4

What is the function of mitochondria?

Answer 4

To release energy in the form of ATP during aerobic respiration

Question 5

The inner membrane of a mitochondrion is folded inwards creating extensions called _______

Answer 5

Cristae

Question 6

What is the function of cristae in a mitochondrion?

Answer 6

Increase the surface area for ATP synthesis to occur

Question 7

What is the function of ribosomes?

Answer 7

Site of protein synthesis

Question 8

What is the function of the rough endoplasmic reticulum?

Answer 8

Protein synthesis and transport of proteins

Question 9

What is the function of the smooth endoplasmic reticulum?

Answer 9

Synthesis and transport of lipids

Question 10

What are the 3 main functions of the Golgi apparatus?

Answer 10

• modifying and packaging proteins into secretory vesicles for secretion from the cell
• producing glycoprotein
• forming lysosomes

Question 11

What is the function of lysosomes?

Answer 11

• release hydrolytic (digestive) enzymes when the cell needs to break down worn out organelles
• digest material that has been taken into the cell

Question 12

What are the 4 structural components of the cell membrane?

Answer 12

• PHOSPHOLIPIDS (forming bilayer)
• PROTEINS
• CARBOHYDRATES (glycolipids and glycoproteins)
• CHOLESTEROL (animal cells)

Question 13

Why is it called the fluid mosaic model?

Answer 13

FLUID: individual phospholipid molecules can move around relative to one another
MOSAIC: proteins embedded in the bilayer vary in size and are arranged in a random pattern

Question 14

Function of phospholipids in cell membrane

Answer 14

Form selective bilayer that allows non polar/uncharged molecules through but prevents the passage of polar/charged molecules

Question 15

Function of extrinsic proteins in cell membrane

Answer 15

Associated with one layer only. May act as receptors for hormones

Question 16

Function of intrinsic proteins in cell membrane

Answer 16

Act as channels to allow the passage of polar molecules eg glucose

Question 17

Function of glycocalyx in cell membrane

Answer 17

Act as cell to cell recognition

Question 18

Function of cholesterol in cell membrane

Answer 18

Controls membrane fluidity

Question 19

What is the function of centrioles?

Answer 19

Animal cell only
During cell division, they migrate to opposite poles of the cell and form the spindle

Question 20

What are plasmodesmata and what is their function?

Answer 20

Narrow pores in the cell wall. Fine strands of cytoplasm pass through these connecting one cell to the next, allowing substances to move between them.

Question 21

Why do chloroplasts contain circular DNA?

Answer 21

For self replication

Question 22

What is the function of chloroplasts?

Answer 22

The site of photosynthesis

Question 23

What is the endosymbiotic theory?

Answer 23

Organelles such as chloroplasts and mitochondria were originally free living prokaryotic cells

Question 24

What is a prokaryote?

Answer 24

Single celled organisms lacking membrane bound organelles, such as nuclei, with DNA free in the cytoplasm

Question 25

What is a eukaryote?

Answer 25

Organism made of cells that have membrane bound organelles with DNA within the nucleus in the form of chromosomes

Question 26

Why is a virus not considered living?

Answer 26

They do not have organelles, enzymes, chromosomes or cytoplasm.

Question 27

What is the name of a virus that attacks bacteria?

Answer 27

Bacteriophages

Question 28

What is a virus made up of?

Answer 28

Nucleic acid, surrounded by a protein coat. Some have DNA while others contain RNA

Question 29

What 4 ways can viruses be transmitted?

Answer 29

- aerosol - insect vectors - exchange of bodily fluids - bites

Question 30

What is the definition of an organism?

Answer 30

All the systems of the body working together make an organism, which is a discrete individual

Question 31

What does unicellular mean?

Answer 31

Single celled organisms which carry out all life functions within one cell

Question 32

What does multicellular mean?

Answer 32

Organisms consisting of many specialised cells which form tissues and organs, which have various structures and roles

Question 33

What is differentiation?

Answer 33

The process by which a stem cell becomes specialised into a specific type of cell

Question 34

What is division of labour?

Answer 34

The adaptation of different parts of an organism to carry out different functions. The more advanced the organism the greater the division of labour.

Question 35

Define a tissue

Answer 35

An aggregation of specialised cells carrying out a specific function

Question 36

What are the 4 primary tissue types in the human body?

Answer 36

- Epithelial tissue - Muscle tissue - Connective tissue - Nerve tissue

Question 37

Name the 4 types of epithelial tissue and give an example of where they are found

Answer 37

- Squamous epithelium (mouth, alveoli) - Cuboidal epithelium (kidney tubules, ducts of glands) - Columnar epithelium (stomach, intestines) - Ciliated columnar epithelium (trachea, oviduct)

Question 38

What are the 3 muscle tissue types?

Answer 38

- Cardiac - Skeletal - Smooth

Question 39

Define an organ

Answer 39

An aggregation of several tissues that carry out a specific function for the whole organism

Question 40

Define an organ system

Answer 40

2 or more different organs working together to provide a common function

Question 41

What are the 5 plant tissues?

Answer 41

- Xylem - Phloem - Palisade mesophyll - Spongy mesophyll - Upper epidermis

Question 42

What is the function of the xylem?

Answer 42

Transport of water and dissolved minerals

Question 43

What is the function of the phloem?

Answer 43

Transport of sucrose and amino acids (photosynthates)

Question 44

What is the function of the palisade mesophyll?

Answer 44

Photosynthesis

Question 45

What is the function of the spongy mesophyll?

Answer 45

Some photosynthesis, it provides air space for diffusion of gases in/out of the leaf

Question 46

What is the function of the upper epidermis?

Answer 46

Contains cells that are found on the top surface of a leaf, protected by a waterproof waxy cuticle

Question 47

Define chromatin (found in the nucleus)

Answer 47

Coils of DNA bound to histone proteins