Cell Functions Cell Wall- The outer layer of a plant cell, situated outside of the cell membrane, the cell wall is tough, flexible, and a very rigid layer.Cell Membrane- surrounds the cytoplasm and filters what can and can’t enter the cell. Simple transport does not requires energy because it is heading in the same direction as the other molecules going through the phospholipid bilayer. Facilitated transport is where the molecules move from low to high instead of going high to low. This uses energy as it is going against the flow. Active transport is somewhat more complicated so when one molecule is outside, one molecule will move in side. Osmosis is the diffusion of water that can move across the phospholipid bilayer.Cytoplasm- Is a thick liquid like solution that encloses and fills the cell that is mainly made out of salt, water, and protein and found in eukaryotic cells. In the cytoplasm, there are microparticles that move freely throughout the cell. Glycolysis is conversion of glucose to pyruvate and it happens to form the high amount of ATP. Fermentation and Glycolysis both take place in the cytoplasm. Fermentation is a metabolic process that consumes sugar in the absence of oxygen.Mitochondria- The mitochondria is the powerhouse for all cells because, all the energy is produced in the mitochondria. Aerobic respiration is a process of breaking down cellular energy with oxygen involved. Cells break down food in the mitochondria that roughly produce 36 ATP (Adenosine Triphosphate). This is the first step in glycolysis, then followed by the second is called the citric acid cycle or the Krebs cycle and the third step is the electron transport system. Chloroplast- is an organelles found only in plant cells which are used to capture the sunlight to produce food by photosynthesis. Photosynthesis is the process by which autotrophs, such as plants and algae, store energy from the sunlight with chlorophyll and use this energy to convert carbon dioxide and water into simple sugars.Vacuole- The vacuole is a membrane-bound fluid filled space inside of the cytoplasm and used for temporary storage of materials. Nucleus- The nucleus is the house of genetic material and it is found only in eukaryotic cells. It is the most important parts in the cell. In eukaryotes DNA replication occurs in the nucleus and DNA replication basically produces two identical genes. Transcription is a step in gene expression which means a particular area in DNA is copied into RNA by the enzyme known as RNA polymerase.Ribosomes- Ribosomes are a non-membrane bound organelle in the nucleus where enzymes and other proteins are assembled. During translation, the ribosomal subunits assemble together like a sandwich on the strand of mRNA, then they attach the tRNA(Transfer Ribonucleic acids) molecules. Cell TypesProkaryotic cells are unicellular organisms that don’t have organelles and membrane-bound structures. Eukaryotic cells have a nucleus and are multicellular and have membrane bound organelles. Prokaryotic and Eukaryotic have cytoplasm but, the cytoplasm in prokaryotes store DNA. Both prokaryotic and eukaryotic cells have ribosomes inside of their cells which help in making proteins. Both eukaryotes and prokaryotes have vacuoles inside of their cells. Prokaryotic cells divide with binary fission, while eukaryotic cells divide with mitosis and meiosis. Eukaryotic cells have a nucleus while prokaryotic cells have nucleoid which contains all genetic material but, not surrounded by nuclear membrane. Animal cells are enclosed by a plasma membrane and have a membrane-bound nucleus and organelles. Plant cells are multicellular organisms with very large vacuoles for storage. Plants have chloroplast to produce food like autotrophs. Protist cells can vary in shapes and sizes, with special body parts such as pseudopod or cilia etc. Some protists are multicellular and some are unicellular, which is unique compared to other organisms. Fungus cells can also be multicellular or unicellular. Fungus, animals, and plants all have somatic cells and reproductive cells. Reproductive cells take in nutrients during the interphase, to double their chromosomes, and divide the cells. Somatic cells are the majority in the body except the reproductive cells so, they would execute most of the functions of the body. The reproductive cells are the cells that make reproduction possible. The reproductive cells are sex cells, the sperm in the male and the egg in the female.When the sperm and egg come together, a lot of cells will be made together including stem cells. There are two types of stem cells, embryonic stem cells and somatic stem cells. Embryonic stem cells are pluripotent stem cells that come from the inside cell mass of a blastocyst. This is an early-stage pre-implantation embryo. Somatic stem cells ( Adult stem cells) have been identified in many organs and tissues, including brain, peripheral blood, bone marrow, etc. These are differentiated while the embryonic stem cells are undifferentiated. Gene expression are the characteristics in a phenotype that is to a specific gene or trait. Cellular differentiation is a process in which a less specialized cell becomes a more specialized cell. Differentiation occurs many times during the development of a multicellular organisms. When genes are not passed down correctly mutations and incomplete genes will be there.Cell Cycle and Cellular Reproduction Cell cycle is life cycle of a cell. It is mainly divided into two major phases, Interphase and Mitosis. The parts of interphase are growth phase 1 ( G1), synthesis (S), Growth phase 2(G2) and Mitosis (M). During G1 ?phase, the cell grows large, and copies organelles, and proteins. In S phase, the cell synthesizes a complete copy of the DNA in its nucleus. It will also copy centrosome, a microtubule organizing structure which later helps to separate DNA during Mitosis. During the G2 ?? phase, the cell grows more and begins to reorganize its contents in preparation for mitosis and G2 phase ends when mitosis begins. During the mitotic (M) phase, the cell divides its copied cytoplasm and DNA to make two new cells. M phase involves two distinct division related processes: cytokinesis which divides cytoplasm and mitosis which results in two daughter cells.The cell can continue to advance in the process of the cell cycle when it has met all of its requirements. The cell has to double up its genes, by copy, synthesize, and prepare for mitosis. Release of excessive hormones can cause problems with growth. This can lead to horrible cell growth and dysfunctional cells. Mitosis is reproduction of somatic cells like skin with a (2N) diploid number of chromosomes. Meiosis is reproduction of sex cells or gametes with a (N) haploid number of chromosomes. In a way they both have more in common with mitosis, because they both start with a diploid number of chromosomes, they both crossover genes as they divide into more cells and they both separate as independent cell.Heredity Heredity is passing of characteristics such as physical or mental from one generation to the next generation. 50% percent of our genes are passed on from our mother and the other 50% are passed on from the father. The human genetic information is stored in the cell nucleus which is the brain of the cell. Animal fur color can be passed on Ex (White GG) (Black gg). So if two bears mate and one is homozygous white and the other is homozygous black. There offsprings will get the dominant gene of the phenotype white as conveniently shown below in Mendelian way. Mendelian Way 100% dominant and 0% recessive. Mutations are things that you can’t expect they happen at random times as mutations are always happening. Sometimes there is no one gene in place for example, hair color. Mutation can occur due to environmental factors and radiation from the sun. Mendel’s results were groundbreaking partly because they contradicted the idea that parents’ traits were permanently blended in their offspring. Codominance occur when both alleles are dominant and expressed simultaneously. In some cases, the phenotype of a heterozygous organism can actually be a blend between the phenotypes of its homozygous parents. One example of codominance is the RS blood groups in humans. A person’s RS blood type is determined by his or her alleles of a certain gene. An L^RSRS, R allele specifies production of an R displayed on the surface of red blood cells, while an L^RSRS, N allele specifies production of a slightly different N marker. Codominance is pretty much two alleles been represented for a trait, but it will not be dominant or recessive. These are non mendelian blood types.Polygenics is inheritance when a large number of genes involved in defining certain traits. It is impossible to isolate effect of each gene to inherent traits. One example to describe polygenic inheritance is height of a person. Height of person does not just depend on genetics, but, it also depends on environmental factors, such nutrition and exercise etc. Human features height, eye color, and hair color come in lots of slightly different forms because they are controlled by many genes, each of which contributes to some amount to the overall phenotype. For example, there are two major eye color genes, but at least 14 other genes that play roles in determining a person’s exact eye color.