The nucleus is a spherical or oval-shaped structure that is usually the most prominent feature of a cell. It is separated from the cytoplasm by a double membrane called the nuclear envelope, which has nuclear pores that control the movement of substances between the nucleus and the cytoplasm. Inside the nucleus are nucleoli, which produce ribosomes, and chromatin, which contains the cell's hereditary units called genes.
A functional ribosome
Tay-Sachs disease is an inherited condition caused by the absence of the lysosomal enzyme Hex A, leading to the accumulation of ganglioside GM2 in nerve cells.
Prophase, metaphase, anaphase, and telophase.
DNA replication must occur before cytokinesis to ensure that each daughter cell receives an identical set of chromosomes.
Anticodon of incoming tRNA
Mitochondria are usually located where oxygen enters the cell or where ATP is used, such as among the contractile proteins in muscle cells.
A highly coiled and folded DNA molecule combined with protein molecules.
Three protein filaments: microfilaments, intermediate filaments, and microtubules.
Synthesizes glycoproteins and phospholipids that are transferred to cellular organelles, inserted into the plasma membrane, or secreted during exocytosis.
Transferring a phosphate group from ATP to a protein to activate it, and their activation and deactivation are crucial in the initiation and regulation of DNA replication, mitosis, and cytokinesis.
Mitochondria are the site of aerobic cellular respiration reactions that produce most of a cell’s ATP and play an important early role in apoptosis.
Cytokinesis begins during anaphase and is completed after telophase.
S phase
They separate
Genomic medicine aims to address disorders such as hypertension, obesity, diabetes, and cancer.
RNA polymerase attaches to the DNA at a special nucleotide sequence called a promoter, which is located near the beginning of a gene.
During translation, the RNA attaches to a ribosome, where the information contained in RNA is translated into a corresponding sequence of amino acids to form a new protein molecule.
Diploid cells are somatic cells that contain two sets of chromosomes.
An orderly, genetically programmed cell death where the cell shrinks and pulls away from neighboring cells.
Chromatin fibers condense into paired chromatids, the nucleolus and nuclear envelope disappear, and each centrosome moves to an opposite pole of the cell.
Proteasomes are responsible for the continuous destruction of unneeded, damaged, or faulty proteins.
Chromatin is a complex of DNA, proteins, and some RNA found within the nucleus. It appears as a diffuse, granular mass in cells that are not dividing and has a beads-on-a-string structure.
It enters the E site and is released from the ribosome
DNA is packed in the nucleus by coiling around histones to form nucleosomes, which further coil into chromatin fibers and eventually condense into chromatids before cell division.
During transcription, the genetic information represented by the sequence of base triplets in DNA serves as a template for copying the information into a complementary sequence of codons.
Transcription occurs in the nucleus and its purpose is to copy the genetic information in DNA to RNA.
Synthesizes fatty acids and steroids, inactivates or detoxifies drugs, removes phosphate group from glucose-6-phosphate, and stores and releases calcium ions in muscle cells.
During the G1 phase, the cell is metabolically active, replicates most of its organelles and cytosolic components, and begins replication of centrosomes.
The plane of alignment of the centromeres of chromatid pairs at the center of the mitotic spindle during metaphase.
The cell is metabolically active, duplicates most of its organelles and cytosolic components, and begins replication of chromosomes.
Protein synthesis ends when the ribosome reaches a stop codon at the A site, causing the completed protein to detach from the final tRNA.
The E (exit) site binds tRNA just before it is released from the ribosome.
Lysosomes digest substances that enter a cell via endocytosis, carry out autophagy, implement autolysis, and accomplish extracellular digestion.
The mitotic spindle is responsible for separating the chromosomes during mitosis.
Regular exercise can lead to an increase in the number of mitochondria in muscle cells, allowing them to function more efficiently.
Mitochondria play an important early role in apoptosis.
Protects cellular contents, makes contact with other cells, contains channels, transporters, receptors, enzymes, cell-identity markers, and linker proteins; mediates entry and exit of substances.
The enzyme RNA polymerase catalyzes the transcription of DNA.
During transcription, the information encoded in a specific region of DNA is transcribed (copied) to produce a specific molecule of RNA.
A balance between cell proliferation and cell death.
Proteasomes degrade unneeded, damaged, or faulty proteins by cutting them into small peptides.
Reproductive cell division is the mechanism that produces gametes through a special two-step division called meiosis.
The phase where the parent cell produces identical cells with identical chromosomes, and chromosomes are visible under a light microscope.
The anticodon of another tRNA with its attached amino acid pairs with the second mRNA codon at the A site.
Nucleoli are spherical bodies within the nucleus that function in producing ribosomes. They are sites of synthesis of rRNA and assembly of rRNA and proteins into ribosomal subunits.
The kinetochore is a protein complex that attaches to microtubules of the mitotic spindle.
Mitochondrial cristae are a series of folds in the internal mitochondrial membrane.
Transfer RNA (tRNA) binds to an amino acid and holds it in place on a ribosome until it is incorporated into a protein during translation. One end of the tRNA carries a specific amino acid, and the opposite end consists of a triplet of nucleotides called an anticodon.
A pair of centrioles plus pericentriolar matrix.
The cell cycle is an orderly sequence of events in which a somatic cell duplicates its contents and divides in two.
Cyclins switch Cdk's on and off, triggering various events that control cell division.
During the G2 phase, cell growth continues, enzymes and other proteins are synthesized in preparation for cell division, and replication of centrosomes is completed.
Replication of DNA and centrosomes.
Several ribosomes attached to the same mRNA, allowing the translation of one mRNA into several identical proteins simultaneously.
The initiator tRNA binds to the start codon (AUG) on mRNA, where translation begins, and carries the amino acid methionine.
Side effects include nausea, diarrhea, hair loss, fatigue, and decreased resistance to disease.
The nuclear envelope is a double membrane that separates the nucleus from the cytoplasm. It has nuclear pores that control the movement of substances between the nucleus and the cytoplasm.
A nucleosome is a bead-like structure in chromatin, consisting of double-stranded DNA wrapped twice around a core of eight proteins called histones.
Large particles enter and exit the nucleus through nuclear pores.
The human genome contains about 30,000 genes.
Fluid in which many of the cell’s metabolic reactions occur.
A membranous network of flattened sacs or tubules; Rough ER is covered by ribosomes and attached to the nuclear envelope; Smooth ER lacks ribosomes.
The Golgi complex accepts proteins from the rough ER, forms glycoproteins, glycolipids, and lipoproteins, and sorts and packages molecules for transport to their destinations.
The three phases of interphase are G1, S, and G2.
A component of the large ribosomal subunit catalyzes the formation of a peptide bond between methionine and the amino acid carried by the tRNA at the A site.
Alternative splicing is a process where pre-mRNA is spliced in different ways to produce several different mRNAs, which are then translated into different proteins.
A neoplasm or tumor is a mass of cells resulting from uncontrolled cell division.
Some anticancer drugs work by inhibiting the formation of the mitotic spindle, thereby stopping cell division.
New peroxisomes can form by enlarging and dividing from preexisting ones or by accumulating components at a site in the cell and assembling.
Genes are the cell's hereditary units that control cellular structure and direct cellular activities. They are located within the nucleus, arranged along chromosomes.
P site
Amino acid on tRNA at P site
Genomics focuses on the study of the relationships between the genome and the biological functions of an organism.
Cilia move fluids over the cell’s surface; flagella move the entire cell.
To remain alive and functioning without dividing, to grow and divide, or to die.
During interphase, the cell replicates its DNA, produces additional organelles and cytosolic components, and undergoes high metabolic activity.
The centromeres split, separating the chromatids, which move toward opposite poles of the cell and are then termed chromosomes.
Introns are regions within a gene that do not code for parts of proteins, while exons are regions that do code for segments of a protein.
Chromatin fibers condense and shorten into visible chromosomes.
Ribosomes are produced in the nucleoli.
Two identical DNA molecules and their histones, held together by a centromere.
Maintains shape and general organization of cellular contents; responsible for cell movements.
A base triplet is a sequence of three nucleotides in DNA.
The two major periods of the cell cycle are interphase and the mitotic (M) phase.
Nuclear pores control the movement of substances between the nucleus and cytoplasm.
Recombinant bacteria produce substances such as human growth hormone (hGH), insulin, interferon (IFN), and erythropoietin (EPO).
The A (aminoacyl) site binds the tRNA carrying the next amino acid to be added to the growing polypeptide.
Peroxisomes protect the cell by containing enzymes that decompose hydrogen peroxide and destroy superoxide, preventing toxic effects.
A centromere holds the chromatid pair together.
The formation of two identical cells through nuclear division (mitosis) and cytoplasmic division (cytokinesis).
Proteasomes degrade proteins into small peptides and amino acids, which can be recycled into new proteins.
Histones (proteins) and DNA.
Cellular contents between plasma membrane and nucleus, including cytosol and organelles.
The mRNA base sequence would be UCGA, and the enzyme that catalyzes DNA transcription is RNA polymerase.
Human cells contain 23 pairs of chromosomes, for a total of 46.
Somatic cell division is the process by which a somatic cell undergoes mitosis and cytokinesis to produce two genetically identical cells.
Cell growth, enzyme and protein synthesis continue, and replication of centrosomes is completed.
Nuclear pores are openings in the nuclear envelope that control the movement of substances between the nucleus and the cytoplasm. Small molecules and ions move through the pores passively by diffusion, while large molecules like RNAs and proteins are transported actively.
The genome is the total genetic information carried in a cell or an organism.
The external mitochondrial membrane and the internal mitochondrial membrane.
During transcription, the bases cytosine (C), guanine (G), and thymine (T) in the DNA template pair with guanine (G), cytosine (C), and adenine (A), respectively, in the RNA strand.
Meiosis is a type of cell division in which the number of chromosomes in the nucleus is reduced by half.
Lysosomes fuse with and digest contents of endosomes, phagosomes, and vesicles, transport final products of digestion into the cytosol, and digest worn-out organelles, entire cells, and extracellular materials.
Actin microfilaments form a contractile ring that pulls the plasma membrane inward, constricting the cell and ultimately pinching it in two.
The tRNA in the P site enters the E site and is subsequently released from the ribosome.
Peroxisomes contain the enzyme catalase to decompose hydrogen peroxide.
Initiator tRNA
It is now at the P site
Chromatin is a complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells.
The proteome refers to all of an organism’s proteins.
A codon is a complementary sequence of three nucleotides transcribed from a DNA base triplet.
Peroxisomes oxidize amino acids and fatty acids and detoxify harmful substances such as hydrogen peroxide and associated free radicals.
Nucleoli produce ribosomes.
The terminator specifies the end of the gene, causing RNA polymerase to detach from the transcribed RNA molecule and the DNA strand.
Because they generate most of the ATP through aerobic (oxygen-requiring) respiration.
Parkinson’s disease and Alzheimer’s disease.
Gene expression is the process where a gene’s DNA is used as a template for the synthesis of a specific protein.
The genetic code is the set of rules that relate the base triplet sequence of DNA to the corresponding codons of RNA and the amino acids they specify.
Cyclin levels rise and fall, determining the timing and sequence of events in cell division.
Chromosomes consist of genes that control cellular structure and direct cellular functions.
When the ribosome reaches a stop codon on mRNA
The goal of the Human Genome Project was to sequence all of the nearly 3.2 billion nucleotides of the human genome.
1. Messenger RNA (mRNA) directs the synthesis of a protein. 2. Ribosomal RNA (rRNA) joins with ribosomal proteins to make ribosomes. 3. Transfer RNA (tRNA) binds to an amino acid and holds it in place on a ribosome until it is incorporated into a protein during translation.
Composed of two subunits containing ribosomal RNA and proteins; they synthesize proteins.
Homologous chromosomes are pairs of chromosomes that contain similar genes arranged in the same or almost the same order.
The nucleus consists of a nuclear envelope with pores, nucleoli, and chromosomes, which exist as a tangled mass of chromatin in interphase cells.
Chromosomal movement stops, and the chromosomes uncoil and revert to chromatin form, with nuclear envelopes forming around each chromatin mass.
It creates a functional ribosome, and the initiator tRNA with its amino acid (methionine) fits into the P site of the ribosome.
Pre-mRNA is the initial transcript that includes information from both introns and exons.
The S phase is the interval between G1 and G2 during which DNA replication occurs.
Recombinant DNA is a combination of DNA from different sources that has been inserted into a host organism to produce proteins it normally does not synthesize.
snRNPs are enzymes that cut out the introns and splice together the exons in pre-mRNA.
The division of a cell's cytoplasm and organelles into two identical cells, usually beginning in late anaphase and completed after telophase.
The resulting two-peptide protein becomes attached to the tRNA at the A site.
The P (peptidyl) site binds the tRNA carrying the growing polypeptide chain.
