Smart Lecture 1 To 5 Notes For BS Biological Science 2022 Free Download
Smart Lecture 1 Notes For BS Biological Science 2022 Free Download
Lecture # 1
Structural and functional unit of life.
Two types of cell
Eukaryotes (unicellular or multicellular).
1.Plasma membrane 2.Cytoplasm 3.Nucleus 4.Endoplasmic reticulum 5.Golgi apparatus 6.vacuoles 7.Lysosomes 8.Plastids 9.Mitochondria 10.Cytoskeleton
1.Protoplasm 2. Cytosol 3. Sol and gel formation 4. Storage house 5. Glycolysis 6. Streaming movements
1. Metabolism of lipids 2. Detoxification of drugs 3. Transmission of nerve impulses
1. Mechanical transport 2. Transport of material 3. Synthesis of protein 4. Storage of compound
Functions of Golgi Apparatus;
1. Cell secretion 2. Transportation 3. Formation of glycolipids
Smart Lecture 2 Notes For BS Biological Science 2022 Free Download
Lecture # 2
What is nucleus?
The nucleus is a membrane-bound organelle that contains genetic material (DNA) of eukaryotic organisms. it serves to maintain the integrity of the cell by facilitating transcription and replication processes. It’s the largest organelle inside the cell taking up about a tenth of the entire cell volume. This makes it one of the easiest organelles to identify under the microscope.
The number of nucleus is vary among cells;
1. Enucleate 2. Mono nucleate 3. Binucleate 4. Poly nucleate
Components of nucleus
1.Phospholipid bilayer membrane 2.Nucleoplasm 3.Nucleolus 4.Chromatin
(phospholipid bilayer membrane)
- The nuclear membrane, like the cell membrane, is a double-layered structure that consists of phospholipids (forming the lipid bilayer nucleus envelope).
- Present on the nuclear membrane are nuclear pores (made up of proteins) through which substances enter or leave the cell (RNA, proteins, etc.). While the lipid bi-layers are separated by a thin space between them (perinuclear cisterna)
Also known as karyoplasm/nucleus sap, the nucleoplasm is a type of protoplasm composed of enzymes, dissolved salts, and several organic molecules.
1. Unlike the nucleus, however, this dense structure lacks its own membrane. 2. During cell division (mitosis), the nucleolus breaks up only to reform from specific sections of the chromosomes after mitosis. 3. The nucleolus is the site of transcription and processing of the ribosomal gene. 4. In some organisms, the nucleus contains as many as four nucleoli.
In the nucleus, chromosomes are thread-like structures made up of strands of DNA and the histone proteins.
Main parts of the chromosome include: Kinetochores Chromatids (each of which consists of the p and q arm) Chromosomes in the nucleus are tightly packed which makes it possible for very large amounts of the genetic material (DNA) to be contained in such a small space (about 3 billion pairs are contained in each cell)
Stretched, DNA in a single cell would be about 2 meters long. Histones are alkaline proteins on which the DNA strands are packed.
Nucleus chemical composition:
1. 9-12 percent DNA 2. 15 percent histone 3. 65 percent enzymes, neutral proteins and acid proteins 4. 5 percent RNA 5. 3 percent lipids
1. Protein synthesis, cell division, and differentiation 2. Control the synthesis of enzymes involved in cellular metabolism 3. Controlling hereditary traits of the organism 4. Store DNA strands, proteins, and RNA
Smart Lecture 3 Notes For BS Biological Science 2022 Free Download
Lecture # 3
The plasma membrane of a cell is a network of lipids and proteins that forms the boundary between a cell’s contents and the outside of the cell. It is also simply called the cell membrane.
Fluid Mosaic Model
Technically, the cell membrane is a liquid. At room temperature, it has about the same consistency as vegetable oil. Lipids, proteins, and carbohydrates in the plasma membrane can diffuse freely throughout the cell membrane; they are essentially floating across its surface.
Plasma Membrane Structure
which spontaneously arrange themselves into a double layer with hydrophilic heads on the outside and hydrophobic tails on the inside.
proteins allow molecules that couldn’t enter the cell otherwise to pass through by forming channels, pores or gates. Proteins in the cell membrane play a role in many other functions, such as cell signaling, cell recognition, and enzyme activity.
Glycoproteins play a role in the interactions between cells, including cell adhesion, the process by which cells attach to each other.
Functions of the Plasma Membrane
A Physical Barrier Selective Permeability Endocytosis and Exocytosis Cell Signaling
- A Physical Barrier
- Selective Permeability
- Endocytosis and Exocytosis
- Cell Signaling
Smart Lecture 4 Notes For BS Biological Science 2022 Free Download
Lecture # 4 & 4.1
- Mitochondria (singular: mitochondrion) are organelles within eukaryotic cells that produce adenosine triphosphate (ATP), For this reason, the mitochondrion is sometimes referred to as “the powerhouse of the cell”. Mitochondria are found in all eukaryotes.
Function of Mitochondria
- Mitochondria produce ATP through process of cellular respiration—specifically, aerobic respiration, which requires oxygen. The citric acid cycle, or Krebs cycle, takes place in the mitochondria.
- The amount of mitochondria in a cell depends on how much energy that cell needs to produce.
- Mitochondria have many other functions as well. They can store calcium, which maintains homeostasis of calcium levels in the cell.
- They also regulate the cell’s metabolism and have roles in apoptosis,
Evolution of Mitochondria
- Mitochondria are thought to have evolved from free-living bacteria that developed into a symbiotic relationship with a prokaryotic cell, providing it energy in return for a safe place to live.
- The idea that mitochondria evolved this way is called endosymbiotic theory.
Smart Lecture 5 Notes For BS Biological Science 2022 Free Download
Lecture # 5, 5.1 & 5.2
Lysosomes are specialized vesicles within cells that digest large molecules through the use of hydrolytic enzymes. Lysosomes are only found in animal cells; a human cell contains around 300 of them. Lysosomes contain over 60 different enzymes that allow them to carry out these processes.
- Lysosomes digest many complex molecules such as carbohydrates, lipids, proteins, and nucleic acids, which the cell then recycles for other uses.
- They can also perform autophagy, which is the destruction of improperly functioning organelles.
- In addition, lysosomes have a role in phagocytosis, which is when a cell engulfs a molecule in order to break it down; it is also known as “cell eating”.
- Lysosomes are formed by budding off of the Golgi apparatus, and the hydrolytic enzymes within them are formed in the endoplasmic reticulum. The enzymes are tagged with the molecule mannose-6-phosphate, transported to the Golgi apparatus in vesicles, and then packaged into the lysosomes.
- Liposomes, not to be confused with lysosomes, are artificially created vesicles that, like all vesicles including lysosomes, have phospholipid bilayers. They are sometimes used to deliver nutrients and pharmaceutical drugs.
- Plastids are double-membrane organelles which are found in the cells of plants and algae. Plastids are responsible for manufacturing and storing of food. These often contain pigments that are used in photosynthesis and different types of pigments that can change the color of the cell.
Types of Plastids
There are different types of plastids with their specialized functions. Among them, a few are mainly classified based on the presence or absence of the Biological pigments and their stages of development.
- Chloroplasts are biconvex shaped, semi-porous, double membrane, cell organelle found within the mesophyll of the plant cell. They are the sites for synthesizing food by the process of photosynthesis.
- Chromoplasts have carotenoid pigments that allow different colors that you see in leaves and fruits. The main reason for its different color is for attracting pollinators.
- These are the non-pigmented organelles which are colorless. Leucoplasts are usually found in most of the non-photosynthetic parts of the plant like roots. They act as a storage sheds for starches, lipids, and proteins depending on the need of the plants. They are mostly used for converting amino acids and fatty acids.
- Eukaryotic cells contain two cylindrical, rod-shaped, microtubular structures, called centrioles, near the nucleus.
- Centrioles form a spindle of microtubules, the mitotic apparatus during mitosis or meiosis.
- When a centriole bears a flagellum or cilium, it is called the basal body.
Functions of Centrioles
- Centrioles are involved in the formation of the spindle apparatus, which functions during cell division.
- The absence of centrioles causes divisional errors and delays in the mitotic process.
- A single centriole forms the anchor point, or basal body, for each individual cilium or flagellum.
- Basal bodies direct the formation of cilia and flagella as well.