Cell Theory and Reproduction Processes in Biology

What is abiogenesis?

The idea that life forms arise from non-living matter.

What is biogenesis?

The principle that life can only come from pre-existing life.

Who conducted an experiment that seemed to support spontaneous generation?

Jan Baptista.

What did Jan Baptista's experiment involve?

He placed grains and sweatshirts in a box for 21 days, resulting in the appearance of mice.

What was Francesco Redi's contribution to disproving spontaneous generation?

He placed meat in flasks, one covered and one uncovered, showing that maggots appeared only in the open flask.

What did Antony van Leeuwenhoek improve?

The simple microscope, achieving a magnification of 200x.

What term did Leeuwenhoek use to describe small organisms he observed?

Animalcules.

What was Louis Pasteur's hypothesis regarding microorganisms?

Microorganisms are present in the air and can produce life under certain conditions.

What was the significance of Pasteur's swan neck experiment?

It demonstrated that microorganisms in the air contaminate sterile solutions.

What did John Needham's experiments aim to confirm?

Leeuwenhoek's results regarding the presence of microorganisms.

What did Hooke discover?

He coined the term 'cell' after observing tiny hollow structures in cork.

What did Schleiden and Schwann contribute to cell theory?

Schleiden discovered that plants are made of cells, while Schwann discovered that animals are made of cells.

What is the cell theory?

1. All living organisms are composed of cells. 2. Cells are the basic units of structure and function in all living things. 3. All cells come from pre-existing cells.

What are the main differences between animal and plant cells?

Animal cells lack chloroplasts and cell walls, are roundish, and have smaller vacuoles, while plant cells have chloroplasts, cell walls, are squareish, and have larger vacuoles.

What are the characteristics of living organisms?

Made of cells, growth, reproduction, energy use, response to stimuli, excretion, respiration, movement, and DNA.

What is DNA?

Deoxyribonucleic acid, a complex molecule in the nucleus that stores information and directs cell activities.

What is the importance of cell division?

It is essential for healing, tissue repair, growth, and reproduction.

What is mitosis?

The process of cell division that results in two identical daughter cells.

What are the phases of the cell cycle?

Interphase, Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis.

What is cytokinesis?

The process of splitting the cytoplasm to form two daughter cells.

What is the difference between sexual and asexual reproduction?

Sexual reproduction involves two parents and genetic mixing, while asexual reproduction involves one parent and no genetic mixing.

What are some types of asexual reproduction?

Budding, fragmentation, sporing, vegetative reproduction, and binary fission.

What is binary fission?

A form of asexual reproduction where a parent cell undergoes mitosis to produce a daughter cell.

What is crossing over?

The process during meiosis where homologous chromosomes exchange segments, creating genetic diversity.

What are haploid and diploid cells?

Haploid cells contain one set of chromosomes (23 in humans), while diploid cells contain two sets (46 in humans).

What is the significance of meiosis?

Meiosis produces four genetically different haploid gametes.

What happens during telophase in meiosis?

Chromosomes reach opposite poles and the nuclear membrane reforms, resulting in haploid cells.

What is the role of centrioles in cell division?

They facilitate the reproduction of cells and aid in the formation of mitotic spindle fibers.