2:Foundations in Biology

Question 1

What is the structure of ribosomes?

Answer 1

• tiny organelles
• 2 sub units

Question 2

What is the function of ribosomes?

Answer 2

To move along the m-RNA molecules and read the nucleotide code to produce proteins

Question 3

What is the structure of Golgi apparatus?

Answer 3

• Stack of membrane bound flattened sacs

Question 4

What is the function of Golgi apparatus?

Answer 4

• lysosome formation
• used in secretion (exocytosis)
• processes proteins (protein modification) - adds sugar and then packages them into vesicles for transport

Question 5

What is the structure of lysosomes?

Answer 5

• Spherical sacs surrounded by a single membrane

Question 6

What is the function of lysosomes?

Answer 6

• contains hydronic digestive enzymes
• breaks down: organelles, ingested material and old cells

Question 7

What is the structure of mitochondria?

Answer 7

• two membranes separated by a fluid filled space
• inner membranes form cristae
• central part is the matrix
• contains it’s own ribosomes and DNA

Question 8

Why do mitochondria have their own ribosomes and DNA?

Answer 8

They have their own ribosomes and DNA to make their own enzymes for efficiency.

Question 9

What is the function of mitochondria?

Answer 9

• produces ATP which releases energy
• carries out aerobic respiration

Question 10

What is the structure of the centrioles?

Answer 10

• Consists of nine sets of tube like structures that form a wall of cylinders.
• Each tube like structure is composed of three tubes called microtubules.
• They are arranged in triplets.

Question 11

What is the structure of the chloroplasts?

Answer 11

• Two membranes separated by a fluid filled space
• Inner membrane has flattened sacs called ‘thylakoids’ where chlorophyll is found
• Contain their own ribosomes and DNA

Question 12

What is the function of the chloroplasts?

Answer 12

• contains chlorophyll to absorb light energy to carry out photosynthesis

Question 13

What is the structure of the vacuole?

Answer 13

• surrounded by a membrane called the tonoplast
• filled with water and solutes

Question 14

What is the function of the vacuole?

Answer 14

• helps maintain structure and stability of the cell when turgid

Question 15

What two groups can prokaryotes be divided into?

Answer 15

• Eubacteria (modern bacteria)
• Archaebacteria

Question 16

What are the main features of prokaryotes?

Answer 16

1) unicellular
2) smaller ribosomes
3) contain plasmids
4) contain pills
5) may have flagella
6) don’t have any membrane bound organelles (nucleus or ER)
7) no cytoskeleton

Question 17

What type of cell wall do prokaryotes have?

Answer 17

Peptidoglycan cell wall, not cellulose

Question 18

Where does respiration occur in prokaryotes?

Answer 18

Mesosomes, not mitochondria

Question 19

What are plasmids?

Answer 19

Small circular pieces of DNA that can carry genes for antibiotic resistance

Question 20

What is the capsule in prokaryotes?

Answer 20

A mucus like protective layer that surrounds many pathogenic bacteria.

Question 21

What is the function of the capsule?

Answer 21

• It protects bacteria from viruses or attacks from a host’s immune system by hiding the antigens on the cell surface.
• It also prevents the cell from drying out

Question 22

How do flagella move?

Answer 22

They are powered by protein motors and required energy for these protein motors to move.

Question 23

How can plasmids be transferred to other bacteria?

Answer 23

Bacteria can conjugate with each other by using pilli, plasmids are shared so they both have an antibiotic resistance.

Question 24

Why don’t prokaryotes have chromosomes?

Answer 24

Their DNA isn’t combined with histone protein (chromosomes are DNA combined with histone protein)

Question 25

What is the cytoskeleton?

Answer 25

An internal framework which is made up of a network of protien fibres

Question 26

What is the function of the cytoskeleton?

Answer 26

- provides strength, stability and support - determines and changes the shape - moves the membrane - hold the organelles in place - helps with movement of organelles

Question 27

What component is cytoskeleton made up of?

Answer 27

- microfilaments - microtubules - centrioles

Question 28

What are microfilaments made of?

Answer 28

Actin Protein

Question 29

What is the function of microfilaments?

Answer 29

- These fibres can move against each other which causes movement in some cells - moves some organelles inside the cell

Question 30

What are microtubules made of?

Answer 30

Tubulin

Question 31

Where are microtubules found?

Answer 31

- eukaryotic flagella - cilia

Question 32

What are the functions of microtubules?

Answer 32

- can move a microorganism through a liquid - can waft a liquid past a cell - other proteins can move organelles along the fibres

Question 33

What are centrioles?

Answer 33

Structures made of protein fibres which are needed for cell division

Question 34

What are the similarities between prokaryotic and eukaryotic cells?

Answer 34

- both contain organelles - their cell surface membrane is made up of a phospholipid bilayer

Question 35

What are the differences between prokaryotic and eukaryotic cells?

Answer 35

- prokaryotic are single-celled - eukaryotes are usually larger and more complex - prokaryotes use binary fission whereas eukaryotes use mitosis and meiosis - prokaryotes don’t have membrane-bound organelles

Question 36

What are the differences between fungal cells and plant cells?

Answer 36

- no chloroplasts - fungal cells can be multicellular - the cell walls of fungi are made of chitin, not cellulose

Question 37

What type of bonding is present in water molecules and why?

Answer 37

Hydrogen bonding - oxygen is more electronegative than hydrogen so it’s a polar covalent bond

Question 38

What are the properties of water?

Answer 38

- cohesive - adhesive - high specific heat capacity - high specific latent heat - good solvent - transparent - ice is less dense than water

Question 39

What is cohesion in relation to properties of water?

Answer 39

It is when water molecules form hydrogen bonds with each other to produce the surface tension of water.

Question 40

What are the benefits of the cohesion of water?

Answer 40

- it explains why the transport stream is maintained in plants - the surface tension can give some organisms a habitat

Question 41

What is adhesion in relation the the properties of water?

Answer 41

Adhesion is when water molecules from hydrogen bonds with other molecules such as cellulose.

Question 42

What is the benefit of water having a high specific heat capacity?

Answer 42

This can reduce the fluctuations of temperature in the organisms body or in their aquatic environments

Question 43

What is the benefit of water having a high specific latent heat?

Answer 43

It maintains habitats of organisms

Question 44

Why is water a good solvent and why is that a benefit for organisms?

Answer 44

Water is a good solvent because polar water molecules can be attracted to opposite charged ions. - therefore it can act as a good transport medium

Question 45

Why is water being transparent beneficial?

Answer 45

It helps with photosynthesis

Question 46

Why is it important that ice is less dense than water?

Answer 46

This is important as when lakes freeze only the top layer is frozen, leaving the water below liquid to maintain habitats.

Question 47

What elements are carbohydrates are made?

Answer 47

- carbon - hydrogen - oxygen

Question 48

What are the examples monosaccharide?

Answer 48

Glucose, fructose, ribose, pentose

Question 49

What are the examples disaccharide?

Answer 49

Sucrose - glucose + fructose Lactose - glucose + galactose Maltose - glucose + glucose

Question 50

What are the examples polysaccharide?

Answer 50

- glycogen - amylose - cellulose - starch

Question 51

What is the general formula for carbohydrates?

Answer 51

C**x**(H2O)**y**

Question 52

How is maltose (malt sugar) formed?

Answer 52

It’s formed from two glucose molecules joined by an alpha 1-4 glycosidic bond

Question 53

How is sucrose (table sugar) formed?

Answer 53

It’s formed from glucose and fructose joined together by alpha 1-4 glycosidic bonds

Question 54

How is lactose (milk sugar) formed?

Answer 54

It’s formed from galactose and glucose joined by beta 1-4 glycosidic bonds

Question 55

What is starch?

Answer 55

A polysaccharide made of two chains - amylose (linear chain) and amylopectin (branded chain)

Question 56

What are the properties of amylose?

Answer 56

1) It is a linear chain folded in an alpha helical shape 2) Good for storage 3) Insoluble water

Question 57

What about glycogen tells us that animals have a higher metabolic rate than plants?

Answer 57

Glycogen is less dense and more soluble than starch, it is broken down more rapidly.

Question 58

What is the structure of glycogen?

Answer 58

Similar to amylopectin (but more branched) - > contains many alpha 1-6 glycosidic bonds

Question 59

What is cellulose made up of?

Answer 59

Beta glucose by 1-4 glycosidic bonds

Question 60

Why is cellulose a straight chain?

Answer 60

The second beta glucose molecule is always rotated 180° so that the OH groups on the first and fourth carbon atoms are positioned in the same direction. - when a polysaccharide is formed this way it cannot form branches so it’s unable to coil.

Question 61

What is the hierarchy for cellulose structure (from smallest to largest)?

Answer 61

Chain of cellulose molecules —> Microfibril —> Macro-fibre —> Cellulose fibres

Question 62

How can you identify the structure of galactose?

Answer 62

If the significant OH groups are on the same side of the oxygen

Question 63

How can you identify the structure of alpha glucose?

Answer 63

If the significant OH groups are on the opposite side of the oxygen

Question 64

How can you identify the structure of beta glucose?

Answer 64

If one significant OH group is on the other side of the oxygen

Question 65

How can you identify the structure of fructose?

Answer 65

If the skeletal structure is in a pentagon shape