What is the Pollinating Agent for Water hyacinth and Water lily?

Aquatic plants are mostly pollinated by water (hydrophilly). For example, in vallisneria, Hydrilla and Zostera water is the source for pollinating flowers. Vallisneria is a dioecious plant meaning both male and female plants are separate.

The female flower reaches on the surface of water by the long stalk while the male flower remains under water. When both flowers mature, staminate flowers release pollen grains on the water surface and reach female flowers through water currents. After pollination and fertilization, the female stalk coils and pulls the fertilized flower below the water surface for further development. Hydrilla and Zostera have male and female flowers on different branches of the same plant. All the above mentioned plants come under submerged category.

However, in free floating aquatic plants such as Eicchornia (water hyacinth), and water lily (Nymphaea) – flowers are present above the water surface. In such plants, pollinating agents are either winds or insects. 

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Why Do Animals Hibernate?

Hibernation is called “winter sleep” in which animals go into a state of inactivity due to cold environmental temperature, short day lengths and limitations of food. It is a survival strategy that animals adopt when the food availability is scarce or difficult to find during a chilly winter season.

During hibernation, animals lower their metabolic processes; it allows animals to use body’s energy reserves at a very slow rate for a long period of time. In other words, hibernation is a means of energy conservation strategy. This way, animals skip the cold and stressful seasons and come out of hibernation when there is abundant of food available and climatic conditions are moderate. Examples of hibernating animals include a variety of amphibians such as frog, reptiles like snakes, insects and mammals like bear and bat. 

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What is Hole in the Heart?

When you hear something like a baby has a hole in her heart -- what do you understand? Does it mean, the heart has a hole on its wall? Well, for a layman, such kind of presumption is obvious, but being a science student, you must know what it means. 

Hole in a heart is associated with congenital heart defects. It means, such kind of problem occurs right from the childhood when a baby is born. It is a very severe heart problem, as it changes the normal flow of blood through the heart. In order to understand the defect, you must know the structure of heart. Mammals, like human beings have four chambered heart -- two auricles and two ventricles. Both auricles and ventricles are separated by a wall called septum. The right side of the heart, means the right auricle and right ventricle is responsible for carrying low-oxygen (impure) blood while the left auricle and left ventricle is responsible for carrying oxygenated (pure) blood. The septum prevents the mixing of pure blood with impure blood. 

A baby having a hole in her heart means that a hole is present between the septum of either the auricles or ventricles. When a hole is present between the auricles, it is called Atrial Septal Defect (ASD) and when a hole is present between the ventricular septum, it is called Ventricular Septal Defect (VSD). Because of the presence of a hole in either atrial or ventricular wall -- the pure blood mixes with the impure one. This leads to the circular of mixed blood throughout the body and into the cells and tissues.

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Pedigree Analysis Tips and Tricks: Part 2 (Question discussion)

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Smart Pedigree Analyisis Tips and Tricks: Part 1

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Digestive System Practice Questions

Q1. A gap between teeth is called:

a) Diastema b) Peristoma c) Dentosa d) Geostema

Q2. Peristalsis occurs in:

a) Stomach b) Esophagus c) Ileum d) Jejunum

Q3. Gastro-esophageal sphincter is present between:

a) Esophagus and stomach b) Stomach and duodenum

c) Duodenum and pancreas d) between duodenum and jejunum

Q4. Zymogen cells secrete:

a) Mucus b) Pepsinogen c) Pepsin d) Rennin

Q5. Which is the largest part of the intestine

a) Duodenum b) Jejunum c) Ileum d) Caecum

Q6. Which of the following is not secreted by Crypts of Leiberkuhn:

a) Lipase b) Maltase c) Aminopeptidase d) Nucleases

Q7. Myenteric nerve plexus is present in:

a) Serosa b) Muscularis c) Submucosa d) Mucosa

Q8. Auerbach’s plexus is present between:

a) Longitudinal and circular muscle

b) Submucosa and mucosa

c) Serosa and muscular is

d) Muscularis and sub mucosa

Q9. Which of the following ions are responsible for the activation of ptyalin:

a) Na+ b) Cl-      c) HCO3- d) SCN-

Q10. How much saliva is secreted per day:

a) 1000 - 1200 ml per day

b) 800 - 1000 ml per day

c) 600 - 800 ml per day

d) 900 - 1200 ml per day

Q11. Which of the following is correct about mucus:

a) It is alkaline and proteinaceous

b) It is acidic and proteinaceous

c) It is neutral and fatty in nature

d) It is neutral and proteinaceous

Q12. Intrinsic factor malsecretion may lead to:

a) Pernicious anemia

b) Rickets

c) Scurvy

d) Dermatitis

Q13, All of the following glands are present in mucosa except:

a) Oxyntic cells

b) Zymogen cells

c) Peptic cells

d) Brunner’s gland

Q14. Intestinal juice is secreted by:

a) Crypts of Leiberkuhn

b) Brunner’s gland

c) Both a and b

d) Gall bladder

Q15. Glisson’s capsule is present in:

a) Liver b) Gall bladder c) Small intesine d) Large intestine

Q16. Which of the following cells are associated with Liver:

a) Kuffer cells b) Paneth cells c) Both a and b d) Argentiffin cells

Q17. The pH of hepatic bile and gall bladder bile are:

a) 8.6 and 7.4 b) 7.4 and 8.6 c) 6.8 and 7.4 d) 7.4 and 6.8

Q18. The main pancreatic duct is also known as:

a) Duct of Wirsung   

b) Duct of Santorini  

c) Sphincter of Boyden

d) Sphincter of Oddi

Q19. The disease gall stone in the gall bladder is known as:

a) Cholethisasis

b) Cholelithiasis

c) Biliary duskiness

d) Sclerosing cholangitis

Q20. Which of the following pancreatic cells secrete pancreatic polypeptide

a) Alpha cells b) Beta cells c) Delta cells d PP cells

Q21. Pancreatic amylase is also known as:

a) Pancreatic acini b) Steapsin c) Proteolase d) Tryptase

Q22. Which of the following cells secrete somatostatin hormone responsible for inhibiting insulin and glucagon

a) Alpha cells b) Beta cells c) Delta cells d PP cells

Q23. Salivary amylase and pancreatic amylase work on pH:

a) 6.8 and 7.5 b) 6.8 and 7.0 c) 7.2 and 7.9 d) 7.2 and 6.8

Q24. Food in the buccal cavity and stomach are respectively called as:

a) Bolus and chyme b) Chyme and bolus c) Chile and bolus  d) Bolus and chile

Q25. Lingual lipase is secreted by:

a) Ebner’s gland

b) Brunner’s gland

c) G-cells

d) Paneth cells

Q26. GIP (Gastric Inhibitory hormone) is secreted by:

a) Epithelium of duodenum

b) Epithelium of stomach

c) Epithelium of Jejunum

d) Epithelium of Ileum

Q27. CCK (cholecystokinin) is responsible for the secretion of:

a) Bicarbonate ions from pancreas

b) Bile from the gall bladder

c) Mucus from the sub mucosa of duodenum

d) Pancreatic juice from the pancreas

Q28. The pH of succus entericcus is:

a) 1.8

b) 6.8

c) 7.8

d) 7.0

Q29. Absorption of water occurs through

a) Osmosis b) Secondary active transport c) Both d) None

Q30. Gross calorific value of fat is:

a) 4.6 Kcal / gm of food

b) 5.65 Kcal/ gm of food

c) 9.45 Kcal / gm of food

d) 9.1 Kcal /gm of food

Q31. Physiological calorific value of fat is:

a) 9.1 Kcal / gm of food

b) 9.45 Kcal / gm of food

c) 9.6 Kcal / gm of food

d) 8.1 Kcal / gm of food

Q32. Choose the correct statement among the following:

a) Intestinal mucosal epithelium has enzymatic cells

b) Ptylin converts protein into proteoses and peptones

c) Crypts of Leiberkuhn are seen between bases of villi in intestine

d) Sphincter of Oddi is present at the junction of esophagus and cardiac stomach

e) Goblet cells secrete hydrochloric acid in stomach

Q33. Enzyme not present in pancreatic juice is:

a) Amylase b) Chymotrypsinogen c) Lipase d) Enterokinase

Q34. The enzymes are location ‘X’ and ‘Y’ are respectively:

Proteins___X____ àProteoses + Peptones ___Y___à Dipeptide

a) Chymotrypsinogen and Pepsin

b) Pepsin and trypsin

c) Ptylin and pepsin

d) Trypsin and dipeptidase

Q35. Chilomicrons are:

a) small fat globules coated with protein

b) protein molecules coated with fat

c) small granules found in gastric juice

d) aerobic microbes

Q36 Which one does not produce any digestive enzymes:

a) Salivary glands b) Pancreas c) Gall bladder d) Stomach

Q37. Which is component of Waldeyer’s ring:

a) Pharynx b) Tonsils c) Ileum d) Esophagus

Q38. Which is not correct:

a) Human saliva is near neutral

b) An adult secretes 1.0 - 1.5 L of saliva per day

c) Saliva is secreted by six pairs of glands

d) Ptylin breaks down cooked starch into maltose

Q39. Which gastric secretion is correctly matched with its source:

a) Pepsin -- Chief cells

b) Chemotropism -- Parietal cells

c) Hcl -- goblet cells

d) Mucus -- Oxyntic cells

Q40. Which enzymes are likely to act on the baked potatoes eaten by a man, starting from mouth and as it moves down the alimentary canal:

a) Disaccharidase like maltase à Lipases à Nucleases

b) Salivary amylase à Pancreatic amylase à Diasaccharidases

c) Salivary maltase à carboxypeptidase à Trypsinogen

d) Pancreatic amylase à Salivary amylase à Lipases

Q41. Absence of enzyme in small intestine will severely affect digestion of proteins:

a) Maltase b) Lipase c) Enterokinase d) Pancreatic amylase

Q42. Which process helps in maintaining blood glucose level under fasting:

a) Glycogenesis b) Glycogenolysis c) Lipogenesis d) Glycolysis

Q43.  Aggregates of lymphoid tissue present in distal part of the small intestine are known as:

a) Villi b) Rugae c) Choroid plexus d) Payer’s patches

Q44. Back flow of faecal matter from large intestine is prevented by:

a) Epiglottis

b) Sphincter of Oddi

c) Ieocaecal valve

d) Gastro-esophageal sphincter

e) Pyloric sphincter

Q45. Special feature of  bile juice is that it

a) has no enzyme b) has amylase c) contains lipase d) contains Hcl

Q46. Bilirubin is formed by breakdown product of:

a) Haempglobin b) Haemocyanin c) Haemoprotein d) Haematin

Q47. In the absence of which of the duodenal enzyme, digestion of chyme proteins not possible:

a) Dil HCl b) Enterokinase c) Gastrin d) All of the above

Q48. Common passage for bile and pancreatic juice is:

a) Ampulla of Vater

b) Duct of Wirsung  

c) Ductus coledochus

d) Duct of Santorini

Q49. Which pair reaches the stomach totally undigested:

a) Fat, cellulose b) Starch, cellulose c) Protein, starch d) Starch, fat

Q50. Which is not a gastrointestinal hormone:

a) CCK b) Gastrin c) Secretin d) Cortisol

ANSWER KEY:

1. a                           11. a                             21. b                               31. a                          41. c

2. b                           12. a                             22. c                               32. c                          42. b

3. a                           13. d                             23. a                               33. d                          43. d

4. b                           14. c                             24. a                               34. b                          44. c

5. c                           15. a                             25. a                               35. a                           45. a

6. c                           16. a                             26. a                               36. c                           46. a

7. b                           17. a                             27. b                               37. b                           47. b

8. a                           18. a                             28. c                               38. c                            48. a

9. b                           19. b                            29. a                               39. a                            49. a

10. a                         20. d                            30. c                               40. b                            50. d

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What is Apomixis and Polyembryony?

In a normal sexual cycle (amphimixis), the megaspore mother cell (2n) of ovule is converted to haploid gametophytic cells (embryo sac) through meiosis (reductional division). This results in the formation of an egg cell, synergids, antipodal cells and polar nuclei cell. Egg fertilizes with the male gamete to form an embryo. This process occurs in almost all angiospermic plants. However, in some plants, meiotic division and fertilization are eliminated still a functional embryo is formed. The formation of embryo without fertilization (by asexual means) is called Apomixis (Apo = not, mixis = act of mixing) and the seed formed is called Apomictic seed.  In other words, apomixis is a type of asexual reproduction that does not involve meiosis and syngamy (fusion of male and female gametes) for the formation of an  embryo.

Apomixis occurs in about 300 species of angioperms that comprises of at least 35 plant species. It is most common in families such as Asteraceae, Graminaceae, Rosaceae and Rutaceae. Some of the most common examples of apomixis include citrus and mango. 

Types of Apomixis:

1. Gametophytic:

a) Diplospory

b) Apospory

2. Sporophytic 

a) Adventive embryony

DIPLOSPORY:

 Megapore mother cell does not go through meiosis. Besides, egg sac organizes normally but the cells are diploid. It is important to note that the embryo develops without being fertilized. This occues because the egg is already growing. Endosperm development may or may not involve fertilization. 

Diplospory is common in grasses and asteraceae family. 

APOSPORY:

In this case, the MMC (megspore mother cell) undergoes meiosis, but the resulting cells degenerate before forming a functional embryo sac. Additional cells present in the nucellus become cytoplasmic and function as apomictic initials. These cells do not undergo meiosis and form their own embryo sac inside the same ovule. 

Apospory condition is found in families such as Rosaceae, Asteraceae and Grasses.

Advantages of Apomixis:

Seeds and plants produced through apomixis are genetically similar to their parent. This technique is can be used in hybrid seed production. We know that hybrid seeds formed in F1 generation is always superior than its pureline parents. However, the same hybrid seeds cannot be used every year due to segregation of characters. And therefore, farmers need to buy hybrid seeds every year for cultivation. However, forming hybrid seeds is a tough task. Using apomictic technique, hybrid seeds can be easily produced in large amounts.

Seed formation through the apomictic process does not require any pollinating agent. 

ADVENTIVE EMBRYONY (POLYEMBRYONY):

In adventive embryony, the megaspore mother cells (MMC) undergoes normal meiotic division and forms a normal embryo sac. Besides, these cells are fertilized normally with male gametes just like normal embryogenesis.  What happens is that the cells in the nucellus become embryogenic and form multiple embryos in the micropylar region of the ovule. The resulting asexual embryos do not form their own embryos rather they grow inside the sexual embryo. This is common in tropical fruit trees such as citrus and mango. 

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THE LIVING WORLD

 Characteristics of Living Organisms:

1. Cellular Structure
2. Metabolism
3. Growth
4. Reproduction
5. Consciousness

Other characteristics of living beings include:

- Adaptation
- Lifespan
- Homeostasis
- Healing and repair
- Movement and variation

Q. What is a defining feature?

A. A feature is said to be defining if it fulfills two criteria:

a) If it is unexceptionally present in all organisms.
b) It should not be part of non-living objects.

1. Cellular Structure: It is the structural and functional unit of life. Cells are present in all living objects. Cells are not present in non-living objects. Therefore, it can be said that cellular structure is a defining feature.

2. Metabolism: (Gk: metabole = change / conversion)

All the organisms are made of chemicals -- these chemicals are constantly being made. These changes are called chemical reactions. All chemical reactions occurring inside our body constitute metabolism.

Metabolism comprises of two events: Anabolism and Catabolism


 

=> These metabolic reactions can occur in vivo or in vitro.

- Metabolism is a characteristic feature of all living organisms and it is absent in non-living objects. It can, therefore, be said that metabolism is a defining feature.

3. Growth:

Growth is defined as an irreversible increase in mass or overall size of our cell / organ or the whole organism. In other words, growth is an increase in body mass.

Growth occurs due to net results of two components of metabolism:

If anabolism > catabolism --- It leads to growth

If anabolism = catabolism --- no growth will occur

If anabolism < catabolism --- it leads to negative growth

Q. Compare plants and animals + growth in living and non-living with respect to growth?





 


 => Since growth is a characteristic of both living and nonliving objects. Growth is, therefore, a non-defining feature.

4. Reproduction:

It is a process of formation / production of offspring having features more or less similar to parents.


Asexual Reproduction: It involves single parent, it is therefore, uniparental. Besides, it does not involve fertilization of gametes.
Types of asexual reproduction:

Fish -- Fission (eg: binary fission in bacteria)

Fry -- Fragmentation (eg: in filamentous algae)

Really -- Regeneration (eg: Planaria)

Very -- Vegetative reproduction

Spicy: sporulation (eg: algae, fungi, bacteria)

Buddy -- Budding (eg: yeast, unicellular fungi, hydra)


Sexual reproduction: It involves two parents = biparental. Besides, it involves the formation of gametes and their fusion.

=> In unicellular organisms, growth and reproduction are synonymous. For instance in bacteria and amoeba -- increase in cell number is associated with the growth. On the other hand, in higher plants and animals, growth and reproduction are mutually exclusive events. A Mutually Exclusive term is used to describe a situation where the occurrence of one event is not influenced or caused by another. Mutually exclusive events never occur at the same time.

- Reproduction is not present universally. For instance Mule (a cross between male donkey [Jack] and female horse [Mare]) and worker bee. Both mule and worker bees are sterile.

=> Since reproduction is somewhere associated with growth in unicellular organisms and since reproduction is not present universally -- it can be considered as a non-defining feature.

5. Consciousness:

It is the ability to sense stimulus / environment and response to it. External stimulus can be physical, chemical or biological. It is unexceptionally shown by all living organisms. It can, therefore, be considered as a defining feature.

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