Chapter 11: Photosynthesis in Higher Plants

Question 1

MELVIN CALVIN born in Minnesota in April, 1911 received his Ph.D. in Chemistry from the University of ___________________

Answer 1

Minnesota

Question 2

Melvin Calvin with co-worker J. A. Bassham studied reactions in green plants forming Sugar and other substances from raw materials like Carbon dioxide, water and minerals by labelling the carbon dioxide with _____________

Answer 2

C¹⁴

Question 3

Calvin proposed that plants change light energy to __________ energy by transferring ___________ in an organised array of Pigment molecule and other substances.

Answer 3

Chemical energy
Electron

Question 4

The Mapping of the Pathway of carbon assimilation in photosynthesis earned Calvin Noble Prize in ________

Answer 4

1961

Question 5

The principle of photosynthesis is established by ______________

Answer 5

Calvin

Question 6

The green Plants make or rather synthesize the food they need through photosynthesis and are therefore called ___________

Answer 6

Autotrophs

Question 7

All other organisms that depend on the green plants for food are called _____________

Answer 7

Heterotrophs

Question 8

Green Plants carry out ___________, a physico-chemical process by which they use light energy to drive the synthesis of organic compounds.

Answer 8

‘Photosynthesis”

Question 9

KOH soaked cotton , which absorbs ___________

Answer 9

CO₂

Note:- experiment you may carried out where a part of a leaf is enclosed in a test tube containing some KOH. on testing for the presence of starch later in the two pars of the leaf, you must have found that the exposed part of the leaf tested positive for starch while the portion that was in the tube, tested negative. This showed that CO₂ was required for Photosynthesis

Question 10

Joseph Priestley (1733-1804) in 1770 performed a series of experiments that revealed the essential role of air in the growth of green plants. Discovered Oxygen in ______________

Answer 10

1774

Question 11

Similar setup as the one used by Priestley, But by placing it once in the dark and once in the Sunlight, ________________(1730-1799) showed that ________________ is essential to the plant process that somehow purifies the air fouled by burning candles or breathing animals.

Answer 11

Jan Ingenhousz

Sunlight

Question 12

In 1854 Julius von Sachs provided evidence for production of Glucose when plants grow, _____________ is usually stored as Starch

Answer 12

Glucose

Question 13

T.W Engelmann(1843-1909) done experiment using a prism he split light into its spectral components and then illuminated a Green alga,___________ , placed in a suspension of aerobic bacteria. The bacterial were used to detect the sites of **O₂ evolution. He observed that the bacteria accumulated mainly in the region of ____________ and ____________ light of the split spectrum.

Answer 13

*Cladophora

Blue
Red

Question 14

Microbiologist, Cornelius van Niel(1897-1985) who based on his studies of __________ and ____________ bacteria, demonstrated that Photosynthesis is essentially a light dependent reaction in which hydrogen from a suitable oxidizable compound reduces Carbon dioxide to Carbohydrate

Answer 14

Purple
Green

Question 15

In green plants H₂O is the ___________ donor and is oxidised to ____________

Answer 15

Hydrogen donor
O₂

Question 16

Cornelius Van Niel inferred that the O₂ evolved by the green plant comes from __________ not from carbon dioxide

Answer 16

H₂O

Question 17

The correct equation, that would represent the overall process of Photosynthesis is

6CO₂ + (__________) ——-Light——> C₆H₁₂O₆ + 6H₂O + 6O₂

Answer 17

12 H₂O

Question 18

The O₂ released is from water; this was proved using ____________techniques

Answer 18

radio isotope

Question 19

The ____________ cells in the leaves, have a large number of chloroplasts

Answer 19

Mesophyll

Question 20

Within the chloroplast there is membranous system consisting of grana, the Stroma Lamellae and the _______________

Answer 20

Matrix stroma

Question 21

The membrane system is responsible for trapping the light energy and also for the synthesis of __________ and ___________

Answer 21

ATP

NADPH

Question 22

In ____________ , enzymatic reactions synthesise Sugar which in turn forms Starch

Answer 22

Stroma

Question 23

The set of reactions, that are directly light driven are called _____________ and the reactions are not directly light driven but are dependent on the products of light reactions (ATP and NADPH) are called ___________________

Answer 23

Light Reactions(Photochemical reactions)

Dark reactions (Carbon Reactions)

Note:- Dark reactions not be construed to mean that they occur in darkness or that they are not light-dependent.
Its just a name given

Question 24

There are _________ type of leaf Pigments

Answer 24

Four

Question 25

Leaf Pigments and their chromatogram colors are:- 1.___________ 2.___________ 3.___________ 4.___________

Answer 25

**Chlorophyll a** (Bright or blue green) **Chlorophyll b** (Yellow green) **Xanthophylls** (Yellow) **Carotenoids** (yellow to yellow-orange)

Question 26

Technique use to separate the leaf pigments is __________________

Answer 26

**Paper Chromatography**

Question 27

**Pigments** are substances that have an ability to absorb light, at specific ______________

Answer 27

**Wavelengths**

Question 28

***Chlorophyll*** _____ is the chief pigment associated with **Photosynthesis** there is maximum absorption by this pigment in the blue and the red region in spectrum of light

Answer 28

Chlorophyll **a**

Question 29

The most of the **Photosynthesis** takes place in the _________ and _____________ regions of the spectrum some photosynthesis does takes place at the other wavelengths of the visible spectrum

Answer 29

**Blue** **Red**

Question 30

Thylakoid pigment like **C**hlorophyll **b** , **X**anthophylls and **C**arotenoids, are called ________________ Pigments. they also protect Chlorophyll **a** from **Photo-Oxidation**

Answer 30

**Accessory pigments**

Question 31

The __________________ phase includes **light absorption**, **water splitting** , **oxygen release** and the formation of high-energy chemical intermediates **ATP** and **NADPH**

Answer 31

**Photochemical**

Question 32

The pigments are organised into **two** discrete photochemical **LHC**(______________________) within the **Photosystem I** (**PS I**) and **Photosystem II**(**PS II**)

Answer 32

**Light harvesting complex**

Question 33

The **LHC** are made up of hundreds of pigment molecules bound to **Proteins**. Each Photosystem has all the pigments (except one molecule of ______________) forming a light harvesting system also called **antennae**

Answer 33

**Chlorophyll a**

Question 34

The **single** ***chlorophyll a*** molecule forms the ____________________ .This is different in both eh photosystems

Answer 34

**reaction centre**

Question 35

In **PS I** the reaction centre ***Chlorophyll a*** has an absorption peak at ______***nm** hence is called **P**________ In **PS II** the reaction centre ***Chlorophyll a*** has an absorption peak at ______***nm** hence is called **P**________

Answer 35

700 , **P700** 680 , **P680**

Question 36

In Photosystem II the reaction centre **chlorophyll a ** absorbs 680 nm wavelength of ____________ light causing electron to become excited and jump into an orbit , these electrons are picked up by an electron acceptor which passes them to an **electron transport system consisting of ______________

Answer 36

**Red** **Cytochromes**

Question 37

The addition of these electrons reduces **NADP^*** to _______________. This whole scheme of transfer of electrons, starting from the _________ , uphill to the acceptor, down the electron transport chain to __________.

Answer 37

**NADPH + H⁺** **PS II** **PS I**

Question 38

Excitation of electrons, transfer to another acceptor, and finally down hill to **NADP^*** reducing it to **NADPH + H⁺** is called the ___________ scheme

Answer 38

**Z Scheme**

Question 39

The **Splitting** of water is associated with the Photosystem _________ ; water is split into 2H⁺, [O] and electrons.This creates ____________, One of the net products of photosysnthesis.

Answer 39

**Photosystem II** **2H₂O ---------> 4H⁺ + O₂ + 4e^-**

Question 40

We need to emphasise here that the **water splitting complex** is associated with Photosystem _________

Answer 40

**Photosystem II** (PS II)

Question 41

The **process** through which **ATP** is **synthesized** by cells (in **mitochondria** and **chloroplasts**) is named ___________________

Answer 41

**phosphorylation**

Question 42

**Photo-Phosphorylation** is the synthesis of **ATP** from **ADP** and inorganic phosphate in the presence of _________________

Answer 42

**Light**

Question 43

When the **two** photosystems work in a series, first **PS II** and then the **PS I**, a process called _________________________ occurs

Answer 43

**non-cyclic photo-phosphorylation**

Question 44

When only **PS I** is functional, the electron is circulated within the photosystem and the phosphorylation occurs due to ______________ flow of electrons. A possible location where this could be happening is in the **stroma lamellae** While the membrane or lamellae of the grana have both **PS I** and **PS II** the stroma lamellae membranes lack **PS II** as well as ____________ reductase enzyme

Answer 44

**cyclic** **NADP** reductase enzyme

Question 45

The cyclic flow, results only in the synthesis of _________, but not of NADPH + H ⁺

Answer 45

**ATP**

Question 46

Cyclic Photophosphorylation also occurs when only light of wavelengths beyond _______ nm are available for excitation

Answer 46

**680 nm**

Question 47

**Chemiosmotic Hypothesis** has been put forward to explain the **mechanism** of how actually ____________ is synthesized in the chloroplast (in photosynthesis) and mitochondria (in respiration)

Answer 47

**ATP**

Question 48

Since splitting of the water molecule takes place on the inner side of the membrane, the protons or hydrogen ions that are produced by the **splitting of water** accumulate within the __________ of the thylakoids

Answer 48

**Lumen**

Question 49

As electron move through the **photosystems**, protons are transported across the membrane. This happens because the primary accepter of electron which is located towards the __________ side of the membrane transfers its electron **not** to an electron carrier by to an **H** carrier

Answer 49

**outer**

Question 50

The **NADP reductase** enzyme is located on the __________ side of the membrane. Along with electrons that come from the acceptor of electrons of **PS I**, ___________ are necessary for the reduction of **NADP⁺** to **NADPH+H⁺**. These protons are also removed from the stroma

Answer 50

**Stroma side** **Protons**

Question 51

**Chemiosmosis** required a membrane, a _______ pump , a proton gradient and __________ synthase.

Answer 51

**proton pump** **ATP synthase**

Question 52

The products of light reaction are __________, __________ and ________

Answer 52

**ATP** **NADPH** **O₂**

Question 53

**O₂** diffuses out of the **chloroplast** while **ATP** and **NADPH** are sued to drive the processes leading to the synthesis of food, more accurately, **sugars**.This is the ____________ phase of **Photosynthesis**

Answer 53

**biosynthetic phase**

Question 54

**Biosynthetic phase** does not directly depend on the presence of light but it dependent on the products of **light reactions**. i.e _________ and __________ ,besides **CO₂** and **H₂O**.

Answer 54

**ATP** **NADPH**

Question 55

Radioisotopes like radioactive **¹⁴C** used by **Melvin Calvin** in **Algal Photosynthesis** studies led to the discovery that the first **CO₂** fixation product was a **3 -carbon**_____________

Answer 55

**organic acid**

Question 56

**Melvin Calvin** also contributed to working out the complete biosynthetic pathway hence it was called ____________ cycle

Answer 56

**Calvin Cycle**

Question 57

The first product of **Calvin cycle**, identified was **3-phosphoglyceric acid** or in short ______________

Answer 57

**PGA** Note: 3 carbon atom in it

Question 58

In some plant the first stable product of **CO₂** fixation was again an organic acid, but one which has **4** carbon atoms in it. This acid was identified to be ________________ or **OAA**

Answer 58

**oxaloacetic acid**

Question 59

**CO₂** assimilation during photosynthesis was said to be of two main types: those plants in which the **first** product is a **C₃** acid (**PGA**) is called ____________ pathway and those in which the **first** product was **C₄** acid (**OAA**) is called _____________ pathway

Answer 59

**C₃ pathway** **C₄ pathway**

Question 60

The primary acceptor of **CO₂** was a ____-**Carbon ketose sugar** -***ribulose bisphosphate***(**RuBp**) in calvin cycle

Answer 60

**5**

Question 61

The _________ pathway occurs in **all photosynthetic plants**; it does not matter whether they have **C₃** or **C₄**

Answer 61

**Calvin**

Question 62

the **Calvin Cycle** can be described under three stages 1. __________ 2. __________ 3. __________

Answer 62

**Carboxylation** **Reduction** **Regeneration**

Question 63

**Carboxylation** is the most crucial step of the **Calvin cycle** where **CO₂** is utilized for the **carboxylation** of ________ . This reaction is catalyzed by the enzyme **RuBP carboxylase** which results in the formation of **2(two)** molecules of _______________

Answer 63

**RuBp** **3-PGA**

Question 64

**RuBp carboxylase** enzyme also has an **oxygenation** activity it would be more correct to call it _______________ or **RuBisCO**

Answer 64

**RuBp Carboxylase-oxygenase**

Question 65

**Reduction** involve utilization of ____ molecules of **ATP** for phosphorylation and ____ of **NADPH** for reduction **per** **CO₂** molecule fixed

Answer 65

**2 molecules** **2 molecules**

Question 66

The fixation of ____ molecules of **CO₂** and **6** turns of the cycle are required for the formation of **one** molecule of **glucose** from the pathway

Answer 66

**Six(6)**

Question 67

Regeneration of **CO₂** acceptor molecule **RuBp** is crucial step which require **One** _______ for phosphorylation to form **RuBp**

Answer 67

**ATP**

Question 68

For ***every*** **CO₂** molecule entering the **Calvin Cycle**, _______ molecules of **ATP** and _____ of **NADPH** are required.

Answer 68

**Three (3)** ATP **Two (2)** NADPH

Question 69

To make **one** molecule of glucose **6** turns of the cycle are required calculate how many **ATP** and **NADPH** molecules will be required to make **one** molecule of **Glucose** _____ **ATP** _____ **NADPH**

Answer 69

18 **ATP** 12 **NADPH**

Question 70

**C₄** pathway plants have the **C₄** __________ acid as the first **CO₂** fixation product they use the **C₃** pathway or the **Calvin cycle** as the main biosynthetic pathway

Answer 70

**Oxaloacetic acid (OAA)**

Question 71

The particularly large cells around the vascular bundles of the **C₄** plants are called **bundle sheath cells** and the leaves which have such anatomy are said to have ___________

Answer 71

**'Kranz' anatomy**

Question 72

**C₄** plants are __________ and _____________

Answer 72

**Maize** **Sorghum**

Question 73

**C₄** pathway is also known as __________________ pathway, is again a cyclic process

Answer 73

**Hatch and Slack**

Question 74

In **C₄**,the primary **CO₂** acceptor is a 3-carbon molecule __________________ and is present in **Mesophyll cells**

Answer 74

**PEP**

Question 75

The enzyme responsible for the fixation of **CO₂** in **C₄** plant is ______________ or **PEPcase**

Answer 75

**PEP carboxylase**

Question 76

In **C₄** plants mesophyll cells lack _____________ enzyme and the **C₄** acid **OAA** is formed in the ____________ cells

Answer 76

**RuBisCO** **Mesophyll cells**

Question 77

**OAA** forms other 4-carbon compounds like malic acid or aspartic acid in the **mesophyll cells itself, which are transported to the ____________ cells

Answer 77

**Bundle sheath cells**

Question 78

In bundle sheath cells **C₄** acids are broken down to release _________ and a 3-carbon molecule , this 3-carbon molecule is transported back to the mesophyll where it is converted to __________ again , thus completing the cycle

Answer 78

**CO₂** **PEP** (phosphoenol pyruvate)

Question 79

In **C₄** , the bundle sheath cells are rich in an enzyme **Ribulose bisphosphate carboxylase-oxygenase (RuBisCO)** but lack ____________

Answer 79

**PEPcase**

Question 80

The _________ pathway is common to **C₃** and **C₄** plants

Answer 80

**Calvin*

Question 81

In **C₃** plants **Calvin pathway** occurs in all the ___________ cells. In **C₄** plants **Calvin pathway** takes place only in the ______________ cells

Answer 81

**Mesophyll cells** (calvin cycle of **C₃**) **Bundle Sheath cells** (Calvin cycle of **C₄**)

Question 82

A light-dependent process that occurs in plants when they take in **oxygen** and release **carbon dioxide** is called ____________

Answer 82

**Photorespiration**

Question 83

____________ that is the most abundant **enzyme** in the world is characterised by the fact that its active site can bind to both **CO₂** and **O₂**

Answer 83

**RuBisCO**

Question 84

**RuBisCO** has a much greater affinity for _____________ when the **CO₂**:**O₂** is nearly **equal**.

Answer 84

**CO₂**

Question 85

In **C₃** plants some **O₂** does bind to **RuBisCO**, and hence **CO₂** fixation is decreased. Here the **RuBP** instead of being converted to 2 molecules of **PGA** binds with **O₂** to form one molecule of **Phosphoglycerate** and **Phosphoglycolate** (2 carbon) in a pathway called __________________

Answer 85

**Photorespiration**

Question 86

In the **Photorespiratory** pathway, there is **neither synthesis** of _________ nor of ___________ rather it results in the release of **CO₂** with the utilisation of **ATP**

Answer 86

**Sugar** **ATP**

Question 87

In Photorespiratory pathway there is no synthesis of **ATP** or ___________

Answer 87

**NADPH**

Question 88

**Photorespiration** does not occur in _______ plants

Answer 88

**C₄**

Question 89

__________ plants show **tolerance** to **higher temperature**

Answer 89

**C₄**

Question 90

If a chemical process is affected by more than one factor, then its rate will be determined by the factor which is **nearest** to its **minimal value** it is the factor which directly affects the process if its **quantity is changed** this law is known as _____________________

Answer 90

**Law of Limiting Factors** (**Blackmsn's** 1905)

Question 91

Increase in incident light beyond a point causes the breakdown of **chlorophyll** and a decrease in ______________

Answer 91

**photosynthesis**

Question 92

_______________ is the major limiting factor for photosynthesis.

Answer 92

**Carbon Dioxide**

Question 93

**C₃** plants respond to higher **CO₂** concentration by showing increased rates of photosynthesis leading to higher productivity has been used for some greenhouse crops such as _________ and _________.

Answer 93

**Tomatoes** **Bell Pepper**

Question 94

The **C₄** plants respond to higher temperatures and show higher rate of _________________ while **C₃** plants have a much lower temperature optimum

Answer 94

**Photosynthesis**