Cells: Definition, Structure, Function, Part

Cell Definition

Cells are the smallest structural and functional units of living organisms in the organizational level of life. The word cell comes from the Greek word "Cellula" or "cella" which means empty space. The body of the organism consists of the organ system, organ system composed of organs, organs formed by tissues, and tissues formed from cells. The point is that every living thing has a cell that is the basic constituent of their body. Cells organize and process all the information so that it can perform the function of life in living things.

From the definition of the cell above, then the virus (often modified including living things or not) is not included in living things. Why? Because the virus is aseluler that has no cells. Based on the number of cells, living things composed of many cells are called multicellular organisms, while living things composed of a single cell are called unicellular organisms.

Function Cell

As we have explained above that the cell is the regulator and controller of all activities of the body of living things, both conscious and unconscious. This function is run not only by one cell, but a group of cells that make up the network, then the network with the same purpose will form the organ, then some organs form the organ system, and organ systems form living things (organisms). Robert Hooke was the first scientist to observe cells by accident, he observed the oak cell from the oak plant under a microscope and then found empty hollows like a honeycomb, which was then called a cell. In general, the cell function which also becomes the cell theory is as follows:

1. Cells as a functional unit of the body (The theory proposed by Max schultze)
2. Cells as structural units of the body (Theories proposed by Mathias Jacob Schleiden and Theodor Schwaan)
3. Cells as a unit of growth and development of living things (Rudolf Virchow)
4. Cells as a unitary heredity (inheritance of nature) that can degrade its nature to offspring (The theory was introduced by Walter Sutton and Theodor Boveri)

CELL STRUCTURE AND CELL PARTS

In general, the cell consists of 3 main parts, namely cell membrane, cytoplasm, and the cell nucleus. Cells also have solid components in the cytoplasm called organelles of cells. Organelles - cell organelles have their own functions. Here is an explanation of the Cells.

1. Cell Membrane / Plasma Membrane
A cell membrane is a thin membrane that is the outermost part of the cell, the cell membrane is also often called plasmalemma. The cell membrane is the part that governs the relationship between the components of the cell and the external environment of the cell. Cell membrane consists of lipid (fat) in the form of phospholipids, proteins, and carbohydrates with different compositions depending on the type of cell. As the name implies, phospholipids (fatty compounds) are composed of hydrophilic phosphates (like water) and hydrophobic lipids (fear of water).

Cell membranes are composed of each paired phospholipid (fat) so it is also called lipid bilayer. Proteins belonging to the cell membrane are the protein of the province (peripheral) and intrinsic (integral) proteins. The extrauterine protein (peripheral) is a protein attached to the outer layer of the membrane, whereas the intrinsic protein (integral) is a protein that penetrates the membrane. The bond between the phospholipids and the extrinsic protein will form a membrane called lipoprotein. Cell membranes can have semipermeable properties that are easily passed by various components, can also be selectively permeable which means can only be passed by certain ions only.

Some cell membrane functions include the following:

a. Protect and wrap cell contents.
b. Separate and control the inner cell relationships with outer environments.
c. Regulate the exchange (transport) of substances from within the cell exit or vice versa.
d. Place of a chemical reaction.

2. Cytoplasm (Cell Liquids)
The cytoplasm or cell fluid is the matrix present in the cell membrane other than the cell nucleus (nucleus). The main constituent of the cytoplasm is water that acts as a solvent and the site of chemical reactions. The cytoplasmic matrix is a colloidal (liquid) cytosol (a mixture of two homogeneous substances). The cytoplasmic matrix may change from the gel phase (semisolid) to the sol (liquid) phase. The cytoplasmic matrix has irritability (sensitivity to stimuli) and conductivity (capable of moving or continuing stimulation).

Some cell cytoplasm functions include the following:

a. The site of chemical reactions and metabolism.
b. As a place to maintain the function of cell life.
c. Keeping things inside the cell.
d. Set the transport of substances inside the cell.
e. Energy formation.
f. The place controls the movement of the cell.

These functions are performed by the cell organelles. As we explained earlier that in the cytoplasm there are solid components called cell organelles that have their own specific functions. Cell function is to support the life of the cell.

Some Organel cells include:

a. Mitochondria serve to produce energy.
b. Lysosomes serves to digest in cells.
c. The ribosome, serves as a place of protein synthesis.
d. Endoplasmic Reticulum, serves to Transport various substances in the cell.
e. The Golgi body serves for protein synthesis and associated with the work of ribosomes and endoplasmic reticulum.
f. Microtubules, protect and keep the cell shape.
g. Microfilaments, play a role in the process of cell movement.
h. Chloroplast, serves as a site for photosynthesis in plants.
i. Centrosome (Sentriol), as a place of cell division.
j. and others.

3. Cell Core (Nucleus)
The cell nucleus is a part that is generally round or oval and is often located in the center of the cell or on the edge of the cell. The nucleus is the most important part of cell life. The nucleus has a central function as the controlling center of all cell activity. The cell nucleus is protected by a wall resembling a cell membrane. This protective structure is called the core membrane.

There are several parts of the nucleus, namely:

a. Nucleolus (Core Boy)
The nucleolus is a round structure composed of filaments and component granules. The core child contains RNA, DNA and several proteins that function in ribosome assembly.

In general, the function of the nucleus (cell nucleus) is as follows:

a.1. As a regulator and control center of all cell activities.
a.2. The storage of genetic information for the organism.
a.3. Start and end an action performed by the cell.
a.4. The place of occurrence of a part of the process of cell division.


b. Nucleoplasm (Core Liquid)
Nucleoplasm is a thick liquid resembling jelly containing proteins, ions, enzymes and other components. Nucleoplasms have complex structures and functions because of their many components.

c. Chromatin
Chromatin is a string of fine yarns found in the cell nucleus. Chromatin contains DNA, the substance that stores all the genetic information of a living thing. When the cell division occurs, chromatin will shorten, thicken, and circle to form a chromosome.

Characteristics of Hexapoda (Insects)

Characteristics of Hexapoda (Insects) - Hexapoda is often referred to as insects that have 6 feet.

The word Hexapoda itself comes from the Greek word meaning "6 feet," therefore all members of Hexapoda subfilum have three pairs of legs / 6 pieces.

This is what makes Hexapoda very different from other arthropod groups that have more than 6 legs.

Arthropoda is an animal that has a body of segmented, framed exoskeleton outside and with a relatively symmetrical shape. This primitive species of insect has legs on every part of its body.

Insecta class or insect has 6 legs attached to the chest has a body consisting of three parts, namely the head, chest or thorax and the abdomen or abdomen.

At the head of the insect, there will be a pair of eyes in the form of compound eyes, a pair of tactile and 3 pairs of mouth.

This insect has several types of mouth types, namely the type of mouth bite/cockroach, the type of mouth bite and the licker on the bee, the type of sucking mouth in butterflies and the type of piercing in mosquitoes. Types of respiratory equipment possessed by insects in the form of trachea and excretion tool in the form of Malpighi body.

The reproduction of insects takes place in a sexual manner with the result of an egg marriage and gradually transforms into an imago.

During the life cycle of the insect undergoes a change of form called the metamorphosis, ie by doing the exfoliation of the skin commonly called ecdysis.

There are two kinds of metamorphosis, ie imperfect metamorphosis or hemimetabolous and perfect metamorphosis or holometabola.

1. Perfect Metamorphosis
perfect morphosis is a metamorphosis that occurs with the developmental stage begins with the egg - larva - pupa - imago. Examples of species with perfect metamorphosis are butterflies and flies.

2. Imperfect Metamorphosis

Imperfect metamorphosis is a metamorphosis that occurs when one of the developmental stages does not take place. Examples of species with imperfect morphoses are crickets, cockroaches, and dragonflies.

Classification of Hexapoda

Order of the Protura

1. Protura is a small whitish Hexapoda with a length of 0.6 - 1.5 mm.
2. Its head is somewhat of a conical shape and has neither eyes nor antenna.
3. The parts of the mouth do not bite but are used to gnaw the food particles which are then mixed with saliva and then sucked into the mouth.
4. The first limb pair functions as sensory and is located in a raised position like an antenna.
5. There is a stile on the first three sections of the abdomen.
6. After hatching from the egg, the Protura abdomen consists of 9 In every 3 subsequent shifts the sections are added to the anterior portion of the tip/telson, so the adult abdomen has 12 segments.
7. These hexapods have habitats in moist soil/ground flowers, live on leaf fungi, at the bottom of the bark and also on deep logs.
8. Type of this type of hexapod food is a decaying organic material and also spores-spores mushrooms.
9. The family of Protura class is Eosentomidae and Protentomidae.

Order of Collembola

1. Another name collembola is a springtail derived from a branching structure/formula that rotates this small hexapode through the air.
2. This animal will make a jump when mating activity.
3. The mouthpiece of the Collembola is rather long and is hidden in the head.
4. Type of food Collembola, in general, is the plants, in addition, there are also omnivorous, and a liquid eater with a mouth shaped like a stilet.
5. This Hexapoda has an emblem like a tube called Collofor which functions in water retrieval.
6. The size of the insects of this spring is very small that is 0.25 - 6 mm.
7. Habitat Collembola in a hidden place like in the ground, in the ruins of leaves or bark, and on the rotting wood and on the fungus.
8. Most ground-dwelling springs feed on decaying vegetation, fungi, and bacteria, while other types of spikes are eating arthropod feces, pollen, algae and other materials.
9. Some types of springtails can sometimes cause damage to gardens and greenhouses.
10. Some families of Collembola or springtails are Entomobryidae, Isotomidae, Hypogastruridae, and Sminthuridae.

Order Diplura

1. The diploma looks like a silver insect and a brittle tail, but this diplomatic order does not have a median tail filament and has only two tail filaments.
2. The body of the diplura is usually not covered with scales and has no compound eyes or single eyes.
3. There are still on the segments of the abdomen 1 - 7.
4. The length of the hexapods is less than 7 mm.
5. The habitat of diplura is in places that are moist in the soil, at the bottom of bark, rocks, caves and other humid places.
6. Some families are often found that Campodeidae, Anajapygidae, and Japygidae.

Main Function of Apical Meristem

The Main Function of the Apical Meristem - The apical meristem is the tip of the plant, and is an undifferentiated meristematic tissue located at the tip of the bud and or at the root of the plant. The main function of the apical meristem is to initiate the growth of new cells at the tip of the shoot and root tip of the plant. Compared to lateral meristems that are more cylindrical, smaller apical meristems.

The apical meristem consists of several layers, the number of layers depending on the type of plant. The tunica layer is the outermost layer and the innermost layer is called the corpus. The monocotyl tunica determines the physical characteristics of the margins and leaf edges, whereas the corpus layer can distinguish the leaf margin characteristics of dikotil plants. Tunica and the corpus play a major role in the physical appearance of plants as every single plant cell is formed from meristems.

Location of Apical Meristem

The apical meristem is located in two locations, namely on the stem and root. Although there are some northern polar plants that have apical meristems in the middle or bottom of plants, such meristems only evolve because they are favorable under certain Arctic conditions.

There are two main types of apical meristems, namely: apical meristem shoot and root apical meristem.

Main Function of Apical Meristem

Apical meristem Is a network that is located at the tip of the root and the end of the stem that serves to form and produce apical buds and apical buds will form new tissues such as roots, branches, and leaves.

The cells found in the apical meristem function as stem cells in the peripheral and surrounding areas, where they multiply rapidly and will turn into primordial leaves or differentiating flowers. This is essentially a place where embryogenesis in flowering plants takes place. Primordial petals, sepals, leaves are ovaries and stamens begin at this site at level one in each time interval, known as plastochron. Information about meristem identity genes.

The apical meristem of the roots produces cells in two different dimensions; They are covered by a root cap for protection against pathogens, grime, and stones. A stationary center lies at the center of the root apical meristem that has low mitotic activity. Newly formed cells in this region are formed in primary root embryos which will give rise to secondary roots.

The Characteristics of Zygomycota

The characteristics of Zygomycota - Zygomycetes is a relatively small group in the mushroom kingdom and belongs to the Zygomycota Phylum.

Zygomycetes include mushroom bread, Rhizopus stolonifer, which rapidly propagates on the surface of bread, fruits, and vegetables. They are mostly terrestrial in their habitats, living on the ground or in plants and animals.

Most species of saprophyte mean they live from decomposing organic matter. Some are parasites in plants, insects, and small animals, while others form a symbiotic relationship with plants.

Zygomycetes play a considerable commercial role. Another species Rhizopus metabolic product is an intermediate in the synthesis of semi-synthetic steroid hormones.

The characteristics of Zygomycota

Zygomycota has the following characteristics:

• The hyphae are not insulated and coenocytic (has several cores).
• Cell walls are composed of chitin.
• Asexual and sexual reproduction.
• Hyphae serve to absorb food, called rhizoid. Example: Rhizopus stoloniferous.

Zygomycota has a coenocytic hifa talus in which the nucleus is haploid when the organism is in a vegetative stage. Fungi usually reproduce asexually by producing sporangiospores. Black tips mushroom bread, Rhizopus stolonifer, is a swollen sporangium packed with black spores. When the spores attach to a suitable substrate, they germinate and produce a new mycelium.

Sexual reproduction begins when conditions become unfavorable. Two opposing mating strains (type + and type -) must be near to gametangia (single: gametangium) of hyphae to be produced and fused, leading to karyogamy.

Developed diploid zygospores have thick coats that protect them from drying and other hazards. They may remain dormant until the environmental conditions become good.

When the zygospore germinates, it undergoes meiosis and produces haploid spores, which will, in turn, grow into new organisms. The form of sexual reproduction in the fungus is called a conjugate (though distinctly different from the conjugation in bacteria and protists), giving rise to the name "conjugated fungus".

Summary

• Most Zygomycota is saprophytes, while some are species of parasites.
• Usually, Zygomycota reproduces asexually by producing sporangiospores.
• Zygomycota reproduces sexually when environmental conditions become unfavorable.
• To reproduce sexually, two opposing mating strains must be fusing or conjugated, thus, sharing the genetic content and creating zygospores.
• The resulting diploid zygospores remain active and protected by a thick coat until environmental conditions have improved.
• When the condition becomes good, zygospore undergoes meiosis producing haploid spores, which will eventually grow into new organisms.
• Karyogamy is a fusion of two nuclei in the cell.
• Conjugation is a temporary fusion of organisms, especially as part of sexual reproduction.
• Zygospores are spores formed by a combination of several zoospores.
• Zygomycetes is an organism of the phylum Zygomycota.

Kingdom Plantae (Plants): Definition, Characteristics, Classification

THE DEFENSE OF KINGDOM PLANTAE

Kingdom Plantae or the Plant Kingdom is one of the multicellular eukaryotic organisms that have cell walls and chlorophyll. Chlorophyll is a green leafy substance that plays a role in the process of photosynthesis so that plants are able to make their own food. The process of photosynthesis can occur with the help of Sunlight. Because plants are able to make their own food, plants are grouped into autotrophic organisms.

Characteristics - KINGDOM PLANTAE

1. Has a Chlorophyll that plays a role in the process of photosynthesis
2. An autotroph (Able to make his own food)
3. It has cell walls composed of cellulose
4. Multicellular Eukaryotic Organisms
5. Store food reserves in the form of starch (starch)
6. Have a hereditary turn in the life cycle.

Kingdom Plantae (Plants): Definition, Characteristics, Classification

CLASSIFICATION OF KINGDOM PLANTAE

The classification of plants is necessary because in this classification we can distinguish plant species from one another. The classification of kingdom Plantae will be discussed below.

Bryophyta Division (Moss Plant)

1. Moss can be found in moist places such as walls, soil, weathered rocks, and bark.
2. Moss likes a humid place because the moss needs water to fertilize. The absence of water causes male sex cells to be unable to fertilize female genital cells.
3. Moss has no phloem and Xylem that serves as a transport vessel. Because moss likes a humid place because there is enough water content.
4. Moss has a root called rhizoid. Rhizoid serves to absorb water and minerals as well as attachment tools.
5. Moss plants are divided into 3 namely Hepaticopsida Class (Lichen Hati), Class Anthocerotopsida (Horn Mosquito) and Class Bryopsida (Leaf Moss).

Pteridophyta Division (Nail Plants / Ferns)

1. Nail plants already have true roots, stems, and leaves. The arrangement of plant leaves spikes like fleece nails.
2. Has a vessel Xylem and phloem.
3. It can live anywhere, especially humid areas such as water, rock surfaces, soil, tropical rainforest and tree bark.
4. It has varied shapes such as sheets, shrubs or deer horns
5. Consisting of 4 classes namely Class Psilopsida (Ancient Nail), Class Lycopsida (Wire Nail), Sphenopsids (Horsetail) and Pteriopsida (True Nail).

Division of Spermatophyta (Seed Plants)

1. High Plants of Kingdom Plantae
2. It has true roots, stems, and leaves and has varying heights and shapes.
3. Produce the seeds as a breeding tool. Reproduction through pollination and fertilization
4. It has a terrestrial habitat and partially in lotus water samples.
5. The spermatophyte division is subdivided into two subdivisions, namely the Gymnospermae subdivision (Open seed plant) and the angiosperms subdivision (covered seed plant).

a. Gymnospermae subdivision (Open seed plant)

a.1. Does not have a seed wrapper. The seeds are open and present on the surface of the fruit leaf
a.2. Consists of woody plants and rooted riding and has a variety of shapes
a.3. Having female and male genitals on one tree but with a separate location.
a.4. Some have different male and female genitals of trees.
a.5. Divided into 4 classes namely Class Cycadinae, class Ginkgoinae, class Coniferae and class Gnetinae.

b. Subdivision of Angiospermae (Closed Seed Plant)

b.1. Seeds are covered by fruit. Plants can be large trees, shrubs, vines and non-woody plants.
b.2. Generally, have flat and wide leaves with varying shapes.
b.3. The reproduction system is a flower that consists of perfect flower and imperfect.
b.4. The perfect flower has male and female genitals while the flower is not perfect only has one or both.
b.5. Reproduction takes place by pollination and fertilization.
b.6. Angiospermae is divided into 2 classes namely Monocotyledons Class (One Piece Beans) and Class Dycotyledone (Shat Two).

b.6.1, Monocotyledons Class (One Piece)

1. Consisting of fibrous roots that are generally not as solid as a taproot root.
2. It has a wide and unbranched stem
3. It has no cambium so it cannot grow bigger
4. Generally, leaves have bones that are parallel or curved
5. The interest has a three-part number
6. Monocots are divided into five orders, namely the Order of Gramineae (Grasses), the Palmae order (palm-pale man), the Order of Zingiberaceae (ginger-ahead), the Order of Bromeliaceae (Pineapple) and Orchidaceae (Orchid).

b.6.2. Dycotyledone Class (Tipped Two)

1. Has solid riding roots.
2. It has cambium so it can grow big.
3. It has a branch that has branches, books, and segments that are not clear
4. Has single or compound leaf and leaf bone or pinnate
5. The interest of dicotyl amounted to a multiple of 2, 4 or 5.
6. Dicotyl plants consist of several orders such as Order of Euphorbiaceae (Gum-sap), Leguminoceae (pod), Solanaceae (Eggplant), Rutaceae (Orange), Malvaceae (Cotton), Myrtaceae (guava) and Compositae.

6 Components DNA sequence

DNA is a genetic material-carrying molecule contained in every nucleus of living organisms including viruses. DNA is a nucleic acid composed of proteins and carbohydrates. DNA is very important for living things because it carries genetic information that determines the nature or form of these living things. There are six components of a series of DNA arranged in a double helix structure.

Read related: DNA Structure

Here are six components of DNA sequencing. Immediately we see the first:

1. Deoxyribose
2-deoxyribose or deoxy is a monosaccharide with the molecular formula H- (C = O) - (CH2) - (CHOH) 3-H. This sugar has five carbons and is a ribose sugar that loses one oxygen atom. Deoxyribose binds to phosphate groups and nitrogenous bases (cytosine, thymine, adenine, or guanine).

2. Phosphate Cluster
Phosphate is a non-organic element with a molecular formula of PO43-. This element acts as a buffering agent.

3. Cytosine
Cytosine (cytosine) is one of four nitrogenous bases. In the gene, cytosine is denoted by the letter C. In DNA, cytosine binds to guanine and forms three hydrogen bonds (in the form of dotted lines).

4. Thymine
Thymine is one of four nitrogenous bases. Thymine is also called 5-methyluracil. In RNA, thymine is replaced by uracil. In DNA, thymine binds with adenine to form two hydrogen bonds. In genes, thymine is denoted by the letter T.

5. Adenine
Adenine (adenine) is one of four nitrogenous bases. In addition to being one of the components of DNA, adenine is also part of energy-rich ATP (adenosine triphosphate). In genes, adenine is denoted by the letter A.

6. Guanine
Guanine (guanine) is one of four nitrogenous bases. In DNA, guanine binds to cytosine and sets up three hydrogen bonds. In genes, guanine is denoted by the letter G.