Cell and Molecular Biology: Concepts and Experiments - Essay Example

Prokaryotes are usually unicellular whereas eukaryotes are usually multicellular. A prokaryotic cell usually has no membrane-bounded organelles whereas membrane-bounded organelles are a characteristic feature of eukaryotic cells. The nucleus in eukaryotic cells is membrane-bounded whereas in prokaryotic cells no membrane-bounded or definite nucleus is present but, a nucleoid is observed. DNA is present in the form of nucleoids in prokaryotic cells whereas DNA in eukaryotic cells is present inside the nuclei in the form of chromatin. Ans2. Mitochondria are composed of two membranes.

An outer membrane forms the outer covering of the organelle and an inner membrane is twisted n folds to form a specific structure called Cistae. There are granules attached in the inner folds of cistae and the inside of a mitochondrial is filled with mitochondrial matrix. The main function of mitochondria is to produce energy for the cell in the form of ATP hence the name ‘powerhouse of the cell’.Ans3. A centrifuge is a process through which we can obtain different cell organelles. The process works in a way that when a solution containing cells is centrifuged, the supernatant fluid containing our required cell organelles separates on the surface which is then collected and observed under the microscope to study the required cell organelle. Ans4. Hemoglobin is present in red blood cells and is a necessary component for living things to survive.

Hemoglobin’s main function is the transport of oxygen. When deoxygenated blood goes through the lungs, the hemoglobin in RBCs attracts oxygen to it. Oxygen binds with hemoglobin in the blood cells and is carried out to the body tissues where it is released from the hemoglobin and blood once again goes to the lungs for oxygenation.Ans5. The main mechanisms of transport through the cell membrane are 1) Diffusion 2) Active transport and 3) passive transport. Diffusion is the simple moving of molecules through the cell membrane across a concentration gradient.

Active transport occurs when a molecule is supposed to be transported against the concentration gradient. Active transport takes place with the help of specific carriers that carry our required molecules against the concentration gradient through specific channels and this process requires energy. Passive transport occurs when a molecule uses another channel to move across the cell membrane. Ans6. Enzymes are catalysts. They work as a catalyst in cellular reaction by either speeding up or decreasing the rate of reaction hence affecting it and not getting used up in the reactionAns7.

DNA consists of two ribose sugar strands which are joined by nucleic acids Adenine, Guanine, Cytosine, and Thymine. These bases form the inner part of the strands and the outer part is formed by ribose phosphate sugar. The strands are twisted around each other to form a double helical structure form a molecule of DNA.Ans8. DNA is double-stranded whereas RNA is single-stranded. In RNA the Thymine base of DNA is replaced by uracil. DNA is deoxyribonucleic acid whereas RNA is simple ribonucleic acid.Ans9.

A chromosome is usually X shaped. The two arms of X are joined by a centromere and it is the point where it divides into two during meiosis.Ans10. Mitosis occurs in all the growing cells of the body whereas meiosis occurs only in the sex cells of the body. Mitosis is the type of division that produces two daughter cells and consists of four phases 1) Prophase, 2) Metaphase, 3) Anaphase, and 4) Telophase and the number of chromosomes is reduced to half after mitosis. Meiosis produces 4 daughter cells and consists of Prophase 1 & 2, Metaphase 1& 2, Anaphase 1 & 2, and Telophase 1& 2.

The number of chromosomes, after the first division remains the same but, the second phase of meiosis is just like mitosis, and the number of chromosomes is reduced to half. There is no exchange of genes in mitosis but the exchange of genetic material takes place in meiosis 1 during a process called Crossing over. Section structure and function of proteins are one of the three basic structural units of the body. Proteins are also included in essential nutrients that we need to take for our body to perform properly.

Proteins are composed of amino acids. Different amino acids combine in different patterns to form a complex chained structure called proteins.