Unit 2 Topic 3

Question 1

What is the function of the cell surface membrane in prokaryotes

Answer 1

• As bacteria does not contain mitochondria, the cell membrane is the site of some respiratory enzymes

Question 2

What are mesosomes

Answer 2

• Infoldings in the cell membrane of some bacteria
• Involved with enzyme activity or photosynthesis

Question 3

What are capsules for prokaryotes

Answer 3

• A slime layer around the cell wall
• Made of starch, gelatin, protein or glycolipids
• Protects bacteria from phagocytosis

Question 4

What are pili

Answer 4

• Projections in some bacteria
• Used in attatchment to the host cell or in sexual reproduction

Question 5

What is the flagella

Answer 5

• Made of flagellin protein
• Allows bacteria to move by rapid rotations

Question 6

What is a nucleoid

Answer 6

• The area in which the genetic material is found
• Genetic material is a single chromosome, made up of circular coiled DNA molecule

Question 7

What are plasmids

Answer 7

• Small circles of DNA, found in some bacteria
• They code for a particular aspect in the bacterial phemotyple
• They replicate themselves independent of the nucleoid
• Can be transferred from one bacterium to another through pili in sexual reproduction

Question 8

What is 70s ribosomes involved in

Answer 8

Protein synthesis

Question 9

What is the bacterial cell wall

Answer 9

• Formed of peptidoglycan
• Prevents swelling and bursting of the cell as the bacteria contents are hypertonic to their medium

Question 10

Describe the structure of the mitochondria

Answer 10

• They are surrounded by an outer and an inner membrane
• The inner membrane is folded into cristae surrounded by a fluid matrix
• Contain mitochodrial DNA that helps replicate the mitochondria during cell division under the control of the nucleus
• They contain 70S ribosomes

Question 11

What are centrioles

Answer 11

• There are 2 centrioles near the nucleus
• Each centriole is made up of 9 grouples of tubules, each is composed of 3 tubules
• They are involved in cell division where wach centriole produces spindle fibres involved in the movement of the chromosomes

Question 12

What is the cytoskeleton

Answer 12

• Web-like structure tht fills the cytoplasm
• Made up of microfilaments and microtubules
• Gives the cytoplasm structure and keeps the organelles in place
• They help cell movement and transport within the cell

Question 13

What are lysosomes

Answer 13

• Spherical bodies in the cytoplasm, they contain digestive enzymes
• They fuse to a membrane bound organelle containing food or an obsolete organelle
• The enzymes break down the contents into materials that can be reused

Question 14

What are the 2 types of endoplasmic reticulum

Answer 14

• Rough endoplasmic reticulum
• Smooth endoplasmic reticulum

Question 15

Describe the process that occurs in the rER

Answer 15

• ER is covered from outside by ribosomes which make proteins
• rER folds and transports these proteins once they have formed
• The large surface area of ER helps synthesis, storing and transporting proteins within and outside the cell

Question 16

Describe the processin sER

Answer 16

• Involved in the synthesis and transport of steroids and lipids as testostoron ahd cholestorol

Question 17

Describe the properties of the Golgi apparatus

Answer 17

• Made of stack or parallel, flattened membrane pockets
• Formed by vesicles from ER fused together

Question 18

Describe the function of the Golgi apparatus

Answer 18

• Proteins are brought to the Golgi apparatus in vesicles which have been pinched off the ER
• proteins then enter Gogli body stacks to be modified
• Carbohydrates added to protein to form glycoprotein as mucus
• Proteins as digestive enzymes are packed in vesicles to form lysosomes that move to the cell surface membrane, fuse to it and release their contents outside the cell

Question 19

Define tissues

Answer 19

Groups of specialised cells carrying out particular functions in the body

Question 20

Define organs

Answer 20

Structures made of several different types of tissue to carry out particular functions in the body