LEC No 06

 

1. What is the basic unit of life?

The basic unit of life is the cell.

2. What is the function of the cell membrane?

The cell membrane controls the movement of substances in and out of the cell, providing protection and structural support.

3. What are the two main types of cells?

The two main types of cells are prokaryotic and eukaryotic cells.

4. What is the difference between prokaryotic and eukaryotic cells?

Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have a nucleus and membrane-bound organelles.

5. What is the role of mitochondria in a cell?

Mitochondria are responsible for producing energy in the form of ATP through cellular respiration.

6. What is the function of ribosomes in cells?

Ribosomes are responsible for protein synthesis by translating mRNA into proteins.

7. What are the three main parts of a cell?

The three main parts of a cell are the nucleus, cytoplasm, and cell membrane.

8. What is the difference between plant and animal cells?

Plant cells have a cell wall, chloroplasts, and large central vacuoles, while animal cells do not.

9. What is DNA and where is it located in the cell?

DNA (deoxyribonucleic acid) carries genetic information and is located in the nucleus in eukaryotic cells and in the cytoplasm of prokaryotic cells.

10. What are the stages of the cell cycle?

The stages of the cell cycle are interphase (G1, S, G2) and mitotic phase (mitosis and cytokinesis).

11. What is mitosis and what is its purpose?

Mitosis is the process of cell division that results in two identical daughter cells. Its purpose is growth, repair, and asexual reproduction.

12. What is meiosis and how is it different from mitosis?

Meiosis is the process of cell division that reduces the chromosome number by half to form gametes (sperm and eggs). Unlike mitosis, meiosis involves two rounds of division.

13. What is the central dogma of molecular biology?

The central dogma states that genetic information flows from DNA to RNA to protein.

14. What is a gene?

A gene is a segment of DNA that codes for a specific protein or function.

15. What is an enzyme and what is its role in chemical reactions?

An enzyme is a biological catalyst that speeds up chemical reactions without being consumed in the process.

16. What are the four main types of macromolecules?

The four main types of macromolecules are proteins, nucleic acids, carbohydrates, and lipids.

17. What is the function of carbohydrates in living organisms?

Carbohydrates provide energy and serve as structural components in cells.

18. What are lipids and why are they important?

Lipids are fats and oils that store energy, insulate the body, and form cell membranes.

19. What are proteins made of?

Proteins are made of long chains of amino acids.

20. What is the role of nucleic acids in cells?

Nucleic acids (DNA and RNA) store and transfer genetic information.

21. What is osmosis?

Osmosis is the movement of water molecules through a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

22. What is diffusion and how does it work?

Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.

23. What is active transport in cells?

Active transport is the movement of molecules across a membrane against their concentration gradient, requiring energy (ATP).

24. What is photosynthesis and where does it occur in plants?

Photosynthesis is the process by which plants convert light energy into chemical energy (glucose). It occurs in the chloroplasts.

25. What is cellular respiration and what are its stages?

Cellular respiration is the process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water. The stages are glycolysis, the Krebs cycle, and the electron transport chain.

26. What is the difference between aerobic and anaerobic respiration?

Aerobic respiration requires oxygen, while anaerobic respiration occurs without oxygen.

27. What is the structure of a DNA molecule?

DNA has a double helix structure, consisting of two strands of nucleotides twisted around each other, with the bases adenine, thymine, cytosine, and guanine.

28. What is the process of transcription in protein synthesis?

Transcription is the process by which an RNA copy of a gene's DNA sequence is made.

29. What is the process of translation in protein synthesis?

Translation is the process by which the mRNA sequence is used to build a protein by linking amino acids together in the correct order.

30. What is the role of mRNA, tRNA, and rRNA in protein synthesis?

mRNA carries genetic information from DNA to ribosomes; tRNA transfers amino acids to the ribosome; and rRNA makes up the structure of the ribosome.

31. What is a mutation?

A mutation is a change in the DNA sequence that can lead to changes in protein function.

32. What is the theory of evolution by natural selection?

Natural selection is the process by which organisms with advantageous traits survive and reproduce more successfully, passing on those traits to future generations.

33. What are the three types of symbiosis?

The three types of symbiosis are mutualism, commensalism, and parasitism.

34. What is an ecosystem?

An ecosystem is a community of living organisms interacting with their physical environment.

35. What is a food chain and what are its levels?

A food chain is a series of organisms each dependent on the next as a source of food. The levels are producers, primary consumers, secondary consumers, and tertiary consumers.

36. What is the difference between a habitat and a niche?

A habitat is the environment where an organism lives, while a niche is the role or function of that organism in its environment.

37. What are biotic and abiotic factors in an ecosystem?

Biotic factors are living organisms in an ecosystem, while abiotic factors are non-living elements like water, air, and temperature.

38. What is the function of the circulatory system?

The circulatory system transports blood, nutrients, gases, and waste products throughout the body.

39. What is the function of the respiratory system?

The respiratory system facilitates the exchange of gases (oxygen and carbon dioxide) between the body and the environment.

40. What are the parts of the human digestive system?

The human digestive system includes the mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas, and rectum.

41. What is the function of the skeletal system?

The skeletal system provides structure, protection for organs, and enables movement.

42. What are the major components of blood?

The major components of blood are plasma, red blood cells, white blood cells, and platelets.

43. What is the immune system and how does it protect the body?

The immune system defends the body against harmful pathogens by recognizing and destroying foreign invaders.

44. What is homeostasis?

Homeostasis is the process by which the body maintains a stable internal environment despite external changes.

45. What is the role of hormones in the body?

Hormones regulate processes such as metabolism, growth, and reproduction.

46. What is the difference between asexual and sexual reproduction?

Asexual reproduction involves one parent and produces genetically identical offspring, while sexual reproduction involves two parents and produces genetically diverse offspring.

47. What is fertilization?

Fertilization is the process in which a sperm cell combines with an egg cell to form a zygote.

48. What is the role of the nervous system?

The nervous system coordinates and regulates body activities, processing sensory information and directing responses.

49. What is the function of the kidneys in the human body?

The kidneys filter waste from the blood, regulate blood pressure, and maintain electrolyte balance.

50. What is the process of evolution?

Evolution is the gradual change in species over time due to genetic variation and natural selection