Bio-sci

Biology is a branch of science that deals with living organisms and their vital processes. Botany, human biology, microbiology and zoology.

Cells- the smallest living unit in all organisms. All living things are made of cells. Cell comes from other pre-existing cells. Cell has many things inside them. They have genetic information, they can divide.

Cell divides into 2 major groups-

Prokaryotes- bacteria, archaea. Have genetic material, DNA but no nucleus which holds the genetic material and controls the cell’s activities. It has cytoplasm, have ribosomes that are small organelles that make protein, have a cell membrane that controls who goes in and out of the cell, has no membrane bound organelles. unicellular

Eukaryotes- Fungi, animals, protists, plants. Have genetic material, DNA but in nucleus, have cytoplasm have ribosomes that are small organelles that make protein, have a cell membrane that controls who goes in and out of the cell, it has membrane bound organelles

Membrane bound organelles are fancy organelles like the nucleus, mitochondria, and golgi apparatus.

One cell-unicellular

Many cells- multicellular

Organelles-mini organ

Cell membrane/plasma membrane- It’s selectively permeable which means that it only lets certain select materials in and out. By doing so, they keep homeostasis through allowing the fluid movement of the membrane.

Homeostasis is defined as a self-regulating process by which a living organism can maintain internal stability while adjusting to changing external conditions.

Cells contain a cytoskeleton which is a collection of fibers that will provide support for the cells and its organelles

DNA CODES FOR PROTEIN WHICH THE RIBOSOMES MAKE

The nucleus controls cell activities. It tells cells what to do, like what proteins to make, and what lipids to do. Inside it, it has a nucleolus, which is where ribosomes can be produced.

A long strand of DNA- Chromatin

To make the nucleus protein it sends messengerRNA to ribosomes to make protein

The nucleus is surrounded by the membrane known as the nuclear envelope, outside of it there’s a hole which is a nuclear pore that allows stuff to go in and out of the cells. It is the center of the cell.

Cells are the smallest living units of an organism. All cells have three things in common, no matter what type of cell they are. All cells have a cell membrane that separates the inside of the cell from its environment. Cytoplasm, which is a jelly-like fluid, and DNA, which is the cell's genetic material. There are two broad categories of cells. The first category is eukaryotic cells. They have organelles which include the nucleus and other special parts. Eukaryotic cells are more advanced complex cells such as those found in plants and animals. The second category is prokaryotic cells. They don't have a nucleus or membrane-enclosed organelles. They do have genetic material, but it's not contained within a nucleus. Prokaryotic cells are always one-celled or unicellular organisms, such as bacteria.

What are organelles?

Organelle means little organ. Organelles are the specialized parts of a cell that have unique jobs to perform.

Organelles like

Nucleus is the control center of the cell.

The nucleus contains DNA or genetic material. DNA dictates what the cell is going to do and how it's going to do it.

Chromatin is the tangled spread-out form of DNA found inside the nuclear membrane. When a cell is ready to divide, DNA condenses into structures known as chromosomes.

The nucleus also contains a nucleolus, which is a structure where ribosomes are made.

After ribosomes leave the nucleus, they will have the important job of synthesizing, or making proteins. Outside the nucleus, the ribosomes and the rest of the organelles float around in the cytoplasm, which is a jelly-like substance. Ribosomes may wander freely within the cytoplasm or attach to the endoplasmic reticulum, sometimes abbreviated as ER. There are two types of ER. Rough ER has ribosomes attached to it. And smooth ER doesn't have ribosomes attached to it. The endoplasmic reticulum is a membrane-enclosed passageway for transporting materials such as the protein synthesized by ribosomes. Proteins and other materials emerge from the endoplasmic reticulum in small vesicles where the Golgi apparatus(Golgi body), receives them. As proteins move through the Golgi body, they are customized into forms that the cell can use. The Golgi body does this by folding the proteins into useable shapes or adding other materials onto them such as lipids or carbohydrates.

Vacuoles are sack-like structures that store different materials.

In plant cell, the central vacuole stores water. In the animal cell, you will see an organelle called a lysosome.

Lysosomes are the garbage collectors that take in damaged or worn-out cell parts. They are filled with enzymes that break down the cellular debris.

The mitochondrion is an organelle that is the powerhouse for both animal and plant cells. It generates most of the chemical energy needed to power the cell's biochemical reactions.

During a process called cellular respiration, the mitochondria make ATP molecules that provide the energy for all of the cell’s activities. Cells that need more energy have more mitochondria. Meanwhile, the cell maintains its shape through a cytoskeleton. The cytoskeleton includes thread-like microfilaments which are made of protein and microtubules which are thin, hollow tubes.

Some organisms such as plants that are photoautotrophic, meaning they capture sunlight for energy, have cells with an organelle called a chloroplast. The chloroplast is where photosynthesis happens. It's green because it has a green pigment called chlorophyll. Plant cells also have a cell wall outside of their cell membranes that shape, support, and protect the plant cell. Animal cells never have a cell wall.

There are many other unique structures that only some cells have. Here are just a few. In humans, for example, the respiratory tract is lined with cells that have cilia. These are microscopic, hair-like projections that can move in waves. This feature helps trap inhaled particles in the air and expels them when you cough. Another unique feature in some cells is flagella. Some bacteria have flagella. A flagellum is like a little tail that can help a cell move or propel itself. The only human cell that has a flagellum is the sperm cell.

In summary, remember, eukaryotic cells are plant and animal cells with a nucleus and membrane-enclosed organelles. While prokaryotic cells are unicellular organisms without these things. All cells have a cell membrane, cytoplasm, and genetic material. And even though only plant cells have chloroplast, both plant and animal cells have mitochondria

ENDOPLASMIC RETICULUM

Golgi body adds lipids and carbs to the protein then after that it will goes out of the cell and travels to the cells membrane where it leaves the cell to perform the function it needs to do. The transport vesicle that surrounds the protein fuses in the cell membrane so it became part of the cell membrane causing the membrane to expand or causing the cell to grow.

MITOCHONDRIA- Its job is to perform cellular respiration, it generates energy by taking the energy stored in the fats and carbs and converts it into a molecule known as ATP. It contains its own DNA.

LYSOSOME- its purpose is to break down foods. It contains digestive enzymes, and it’s inside white the blood cells that can destroy pathogens by breaking down into smaller stuff that can be used/recycled by the cells

Phagocytosis is the process where the white blood cells engulf the pathogens

STRUCTURE OF THE CELL MEMBRANE

When scientists looked at the selectively permeable cell membrane, they described its structure as a fluid mosaic. You might know that a mosaic is a picture made up of little tiles. Like a mosaic, the cell membrane is made up of different parts as well.

The cell membrane has two layers of phospholipids referred to as a lipid bilayer. The lipid bilayer isn't rigid. The phospholipids in it have the ability to move in a flexible wave-like motion. Let's take a closer look at a few phospholipids. The round head portions are hydrophilic, which means they're attracted to water. Both the extracellular fluid, meaning fluid outside the cell, and the cytoplasm inside the cell are mostly made up of water. So, the hydrophilic phospholipid heads of the outer layer will be oriented toward the extracellular fluid. And the heads of the inner layer will be oriented toward the cytoplasm.

The phospholipid tails are hydrophobic, which means watery areas withheld them. So they orient toward each other in a direction as far away from the watery content as possible. There are also scattered proteins embedded in the phospholipid layers, some with carbohydrates attached. So, in the fluid mosaic model, the cell membrane is made up of different parts. And these parts make up a flexible boundary around the cell. But how do the majority of substances get in or out of the cell? Some molecules sip through the little spaces in between the phospholipids, which make up the majority of the semi-permeable cell membrane. However, other molecules are too big to fit through the cell membrane this way. So, how do these larger molecules pass through the cell membrane? The molecules move through proteins embedded in the cell membrane, either from the extracellular area into the cell or from the intracellular area out of the cell. These substances will move through tunnels made up of these proteins.

CELL CYCLE

A somatic cell is any cell in the body of an organism, except for sex cells such as sperm and egg cells. The cell cycle describes the sequence of cell growth and division. A cell spends most of its life a state called interphase. Interphase has three phases, the G1, S, and G2 phases. Interphase is followed by cell division, which has one phase, the M phase. Together these four phases make up the entire cell cycle. G1 of interphase is sometimes called growth 1 or gap phase 1. In G1, a cell is busy growing and carrying out whatever function it's supposed to do. Note that some cells, such as muscle and nerve cells, exit the cell cycle after G1 because they do not divide again. A cell enters the S phase after it grows to the point where it's no longer able to function well and needs to divide. The S stands for synthesis, which means to make, because a copy of DNA is being made during this phase. Once DNA replication is complete, the cell enters the shortest and the last part of interphase called G2, also known as growth 2 or gap phase 2. Right now, it's enough to know that further preparations for cell division take place in the G2 phase. Now that interphase is over, the cell is ready for cell division, which happens in the M phase. The M phase has two events. The main one is mitosis, which is division of the cell's nucleus, followed by cytokinesis, a division of the cytoplasm. So, at the end of M phase, you have two daughter cells identical to each other and identical to the original cell. Let's review. The cell cycle describes the life cycle of an individual cell. It has four phases, three in interphase and one for cell division. Most cell growth and function happen during G1. The cell enters the S phase when it needs to divide. In this phase the cell replicates its DNA. Replication just means the cell makes a copy of its DNA. In G2, the cell undergoes further preparations for cell division. Finally, we have cell division in the M phase. The M phase consists of mitosis, which is nuclear division, and cytokinesis, or division of the cytoplasm. We'll explore the details of mitosis and cytokinesis separately.

M PHASE-

mitosis- a division of nucleus and cytokinesis- a division of cytoplasm

Cell division includes the division of the nucleus, called mitosis, and the division of the cytoplasm, called cytokinesis. Mitosis is further broken down into four phases: prophase, metaphase, anaphase, and telophase. Prophase is the longest phase of mitosis. Prophase is when chromatin begins to condense into the shape of chromosomes, and the nucleolus disappears. The previously replicated DNA coils tightly into sister chromatids. For the first time, you see individual chromosomes. In the center of each chromosome, a centromere attaches the sister chromatids together. Meanwhile, in the cytoplasm, microtubules known as spindle fibers begin to fan out from two sets of paired structures called centrioles. The spindle fibers elongate as the centrioles begin moving to opposite sides, or poles, of the cell. While this is happening, the nuclear membrane surrounding the nucleus disappears. Now that chromosomes are no longer separated from the cytoplasm, the opposite ends of the spindle fibers can attach to the centromeres. Next, the cell enters metaphase. The centrioles complete their movement to the poles of the cell while the spindle fibers line up the chromosomes along the equator of the cell. The end-to-end alignment of chromosomes results in a sister chromatid on either side of the equator. Anaphase follows metaphase. During anaphase, spindle fibers separate the sister chromatids at their centromere. Once separated from each other, each chromatid is called a chromosome. The single-stranded chromosomes form a V shape as the spindle fibers shorten and drag them through the gel-like cytoplasm. The chromosomes move to opposite poles of the cell toward their centrioles. It's common to confuse centrioles with centromeres which connect chromatids. Remember, centrioles are at the poles. Telophase is the final stage of mitosis. In telophase, a nuclear membrane re-forms around each set of chromosomes. Then the chromosomes spread out into chromatin, and the nucleolus becomes visible once again. Mitosis, the division of the nucleus, is now complete. The final step of the M phase is cytokinesis, the division of the cytoplasm. In animal cells, cytokinesis occurs through the inward movement of the cell membrane. This progressively pinches the cytoplasm until two identical daughter cells form. In contrast, plant cells can't pinch in two because they have a rigid cell wall surrounding their cell membrane. Instead, cell wall material assembles along the equator forming a structure called the cell plate. The cell plate grows until it joins with the existing cell membrane, separating the two halves of the cell into daughter cells. Over time, new cell walls form between the two daughter cells. Here are the key points to remember. The M phase is the fourth and final phase of the cell cycle. During the M phase, cell division occurs through two processes: mitosis, when the nucleus divides, and cytokinesis, when the cytoplasm divides. Mitosis has four phases. During prophase, chromatin condenses into chromosomes, spindle fibers form, and the nucleolus and nuclear membrane disappear. During metaphase, spindle fibers align the chromosomes along the cell equator. In anaphase, the spindle fibers separate sister chromatids into two separate groups of chromosomes, pulling them toward the poles. And in telophase, the nucleolus and nuclear membrane re-form. The chromosomes disperse into chromatin. Cytokinesis is division of the cytoplasm. The M phase is complete after cytokinesis occurs. The M phase of the cell cycle always results in two daughter cells. Both of these daughter cells are identical to each other and identical to the original cell that underwent mitosis.

MEIOSIS

Meiosis, sometimes called reduction division, is the type of cell division that produces gametes. By gametes, we mean sex cells such as sperm cells in males and egg cells in females. Meiosis is broken down into two stages of cell division called meiosis I and meiosis II. Meiosis I has four phases: prophase I, metaphase I, anaphase I, and telophase I. And meiosis II also has four phases: prophase II, metaphase II, anaphase II, and telophase II. Let's look at what happens during meiosis I. Prophase I starts with a diploid cell. Its chromatin contains two uncoiled, spread out sets of chromosomes, one from each parent. After the DNA in the chromatin replicates, it condenses into the more familiar X-shaped chromosomes. The replicated DNA is the same in the identical sister chromatids of each chromosome. In a process called synapsis, each chromosome pairs up with and binds to its corresponding homologous chromosome, forming a tetrad. A tetrad is the group of four sister chromatids in paired homologous chromosomes. The chromosomes contain genetic information called genes. These genes were inherited from each parent, and different versions of the same gene on each chromosome are called alleles. In a process called crossing over, chromatids from each homologous chromosome exchange segments of alleles. Also called recombination, crossing over randomly happens on every chromosome, resulting in different gene combinations. This explains why every gamete is genetically different from every other gamete. Crossing over results in genetic variety in offspring. This is why children are different from their biological parents, as well as from their biological siblings. Continuing on with prophase I, the nuclear membrane disappears, the centrioles move to opposite ends of the cell, and spindle fibers fan out from them. Next, in metaphase I, the homologous chromosomes line up at the equator and attach to spindle fibers from opposite poles. During anaphase I, spindle fibers separate the homologous chromosomes in each tetrad and pull them to opposite poles of the cell. The cell enters telophase I with one chromosome from each homologous pair at separate poles. However, each chromosome still consists of sister chromatids. Keep in mind that each chromosome's sister chromatids are no longer identical because of the allele exchange that happened during crossing over. Then spindle fibers disappear and the nuclear membrane re-forms around the chromosomes. Finally, cytokinesis occurs. Meiosis I ends with two genetically different haploid daughter cells. Each haploid cell contains only one set of chromosomes consisting of paired sister chromatids. Both cells now enter the next stage, meiosis II. However, unlike meiosis I, DNA does not replicate before meiosis II begins. Once again, in prophase II, the nuclear membrane disappears, and spindle fibers fan out from the two sets of paired centrioles. During metaphase II, the chromosomes in each cell line up at the equator and attach to spindle fibers from both poles. During anaphase II, the sister chromatids of each chromosome separate and move to opposite poles. Once the sister chromatids separate, they are called chromosomes. Finally, during telophase II, the spindle fibers disappear, and nuclear membranes re-form, and cytokinesis occurs in both cells. Meiosis II ends with four genetically different haploid daughter cells, each containing only one set of chromosomes. Some key points to remember about meiosis. It begins with a diploid cell. Meiosis only produces gametes. Gametes are genetically different haploid cells, sperm cells in males and eggs in females. Meiosis has two stages of cell division called meiosis I and meiosis II. During meiosis I, homologous chromosomes separate to produce two haploid cells, each containing chromosomes in the form of paired sister chromatids. In meiosis II, the sister chromatids separate in both cells, becoming individual chromosomes. Cytokinesis of these cells produces four genetically different haploid gametes. And here are some key points to remember about prophase I. The pairing of homologous chromosomes called synapsis occurs. Each pair of homologous chromosomes, consisting of four chromatids, is called a tetrad. During the process of crossing over, chromosomes in homologous pairs exchange segments of alleles. Crossing over results in genetic differences in gametes. All gametes produced by meiosis are haploid.

MITOSIS VS MEIOSIS

two types of cell division, mitosis and meiosis. While mitosis occurs all over the body in somatic cells, meiosis only occurs in the reproductive cells of the gonads in order to form gametes. The original cell in both mitosis and meiosis is diploid. Mitosis consists of one cell division, while meiosis consists of two stages of cell division called meiosis 1 and meiosis 2. Mitosis results in two diploid daughter cells. In contrast, meiosis results in four daughter cells that are haploid gametes. The two daughter cells resulting from mitosis are genetic duplicates of each other and the original cell. But each haploid gamete resulting from meiosis is genetically different from every gamete ever formed

King Charles II

Robert Hooke

Antonie Van Leeuwenhoek

Matthias Jakob Schleiden

Theodor Schwann

Rudolf Carl Virchow

King Charles II- commissioned a microscopic examination of the natural world. focus INSECT ANATOMY.
Robert Hooke- Aside from bugs, he examines every object he finds at home. He devised one of the earliest microscopes. Most commemorative work came from cork tissue. He calls it CELLULAE in Latin word, which means SMALL ROOM

Antonie Van Leeuwenhoek- interest came when he saw Hook’s micrographia. Fist invention was simple microscope with one lens, later on he invented more 500 lenses magnifies 270 times. He discover the living creature in water pond and called it ANIMALCULES which means little animals cuz it’s moving

Matthias Jakob Schleiden- PLANT CELLS

Theodor Schwan- ANIMAL CELLS

Rudolf Carl Virchow- concludes that cells come from pre-existing cells

All organisms are composed of one or more cells( Schleiden, Schwann)

Cells are the smallest unit and the basic unit of structure and function in an organism(Schleiden, Schwann)

Cells arise from previously existing cells or omis cellula e cellula (Virchow)

Nucleus- control and regulates activities of the cell

nucleolus- site for ribosome synthesis

nuclear membrane- protects nucleus, boundary for nucleus and other organelles

endoplasmic reticulum- transportation of substances to golgi body

golgi body- Cell’s post office, transportation of materials within the cell

lysosome- garbage collectors, protects the cell by engulfing foreign bodies

mitochondria- power house of the cell, produces atp, has its own dna

Adenosine Diphosphate- ADP

Adenosine Triphosphate- ATP

Chloroplast- for photosynthesis

chlorophyll- green pigment

vacuoles- store food, water, and other waste materials

cytoplasm- fluid like structure that supports organelles, allows organelles to move freely.

Cells- basic unit of life

2 types of cell

Prokaryotes

*PRO- before KARYON- kernel, nut

*Has no nucleus and membrane-bound organelles

*most dna found in NUCLEOID REGION

Kingdom: bacteria and archaea

Size: Small, unicellular

Sexual Reptoduction: None; Dna transfer through conjugation

Cell division: binary fusion

structure of DNA: circular;haploid

Eukaryotes
*EU- Good, well, true KARYON- kernel, nut

*has nucleus and other organelles are bound by a membrane

KINGDOM: plants, animals, protists

SIZE: large; uni and multicellular

sexual reproduction: meiosis

cell division: mitosis

structure of dna: linear; diploid

Protists- Can provide their food, find their food, and feed off the living host

Archaea- can travel in hot places

Binary fusion- can fertilize itself

Conjugation- transferring ALL materials from bacteria to other bacteria to fertilize

cells specification- all cells have different function to perform that can help our body

Red blood cells- carries oxygen throughout the body
*No nucleus

*Biconcave shape

*contains hemoglobin

White Blood Cells- has an important role in immune system

*irregular shape can produce antibodies and antitoxins

Egg cell- carries genetic materials

*large and bulky

*chemical change in the membrane prevents fertilization of more one sperm

Sperm Cell- fertilize an egg cell to make a baby

*long tail to swim

*numerous mitochondria

* with chemicals on the head for egg cell entry

Muscle cell- facilitate movement

*elongated and elastic

*numerous mitochondria

Nerve cells/ neuron- carry nerve impulses throughout the body

*long, thin axion

*Branching Dendrites

*Myelinated

Stomata/ Guard Cell- Regulates rate of transpiration

*cell wall has varying thickness

root hair cells- absorb water and minerals from the soil

* long and thin with large surface area

Xylem Vessel- transport water and minerals from the roots to other parts of the plants

*has lignin

*No protoplasm'

*Cells form a continuous tube

Photosynthetic cells- produces food through the process of photosynthesis

*contains numerous chloroplast

Cell modification- Adaptation/changes acquired by the cell after the cell division s that aids the cell in various beneficial ways

Cilia- Hair-like organelles extending from the cell surface

types:

non-motile or primary cilia- sensory

motile- movement

flagella- long, whip-like, tail like structure made of protein filaments

*aids in movement

Projections- increases surface area to increase absorption

pseudopods

*false feet

*temporary extension of the cytoplasm

*movement and ingestion(phagocytosis)

MAJOR CELL DIVISIONS

MITOSIS

Mitosis is the process by which somatic (body) cells divide to produce two identical daughter cells, each with the same number of chromosomes as the parent cell. Mitosis is crucial for growth, tissue repair, and maintenance in multicellular organisms.

MEIOSIS

Meiosis is a specialized cell division process that occurs in germ cells (sperm and egg cells) and leads to the formation of haploid cells (gametes) with half the number of chromosomes as the parent cells.

The cell cycle is the series of events that occurs in a cell from one division to the next.

The cell cycle makes it possible for organisms:

• to grow and develop

• to replace cells that are old or damaged,

• to produce new cells.

There are two main phases in the cell cycle:

• Interphase

• Mitotic phase

Interphase is the period of a cell’s growth and development.

• A cell spends most of its life in interphase
•The mitotic phase creates two new identical cells.

Mitosis – is the kind of division that takes place in the somatic or body cells.

Meiosis - a process where a single cell divides twice to produce four cells containing half the original amount of genetic information.

THE CANCER CELL

Cancer is when abnormal cells divide in an uncontrolled way. Some may eventually spread into other tissues. Also, there are more than 200 different types of cancer.

Cancer starts when gene changes make one cell or a few cells begin to grow and multiply too much. This may cause a growth called a tumor.

Some cancers can spread to other parts of the body. - A primary tumor is the name for where a cancer starts. - Cancer can sometimes spread to other parts of the body; this is called a secondary tumor or a metastasis. - Cancer and its treatments can affect body systems, such as the blood circulation, lymphatic and immune systems, and the hormone system.

Carcinoma- A cancer that begins in the skin or in tissues that line or cover internal organs. There are a number of subtypes, including adenocarcinoma, basal cell carcinoma, squamous cell carcinoma, and transitional cell carcinoma.

sarcoma- A cancer that begins in the connective or supportive tissues such as bone, cartilage, fat, muscle, or blood vessels.

leukemia- A cancer that starts in blood forming tissue such as the bone marrow and causes large numbers of a normal blood cells to be produced and go into the blood. “Cancers of blood cells”. A condition in which the bone marrow makes too many white blood cells. The blood cells are not fully formed and so don't work properly to fight infection. The cells build up in the blood.

stages of cancer

Staging is a way of describing the size of a cancer and how far it has grown. Several tests are carried out to check how big the cancer is and whether it has spread into surrounding tissues. They also check to see whether it has spread to another part of the body

stage 1

Usually means that a cancer is relatively small and contained within the organ it started in

stage 2

Usually means the cancer has not started to spread into surrounding tissue but the tumor is larger than in stage 1. Sometimes stage 2 means that cancer cells have spread into lymph nodes close to the tumor. This depends on the particular type of cancer

stage 3

Usually means the cancer is larger. It may have started to spread into surrounding tissues and there are cancer cells in the lymph nodes in the area

stage 4

It means the cancer has spread from where it started to another body organ. This is also called secondary or metastatic cancer.