Science Flashcards
Food starts its journey from the mouth or the oral cavity. There are many other organs that contribute to the digestion process, including teeth, salivary glands, and tongue. Teeth are designed for grinding food particles into small pieces and are moistened with saliva before the tongue pushes the food into the pharynx.
Mouth
A fibromuscular y-shaped tube attached to the terminal end of the mouth. It is mainly involved in the passage of chewed/crushed food from the mouth through the esophagus. It also has a major part in the respiratory system, as air travels through the pharynx from the nasal cavity on its way to the lungs.
Pharynx
This is a muscular tube that connects the pharynx, which is a part of an upper section of the gastrointestinal tract. Located in your throat near your trachea (windpipe)
Esophagus
A series of muscular contractions within the esophagus
Peristalsis
It serves as a muscular bag which is situated towards the left side of the abdominal cavity, beneath the diaphragm.
Stomach
It is an aqueous secretion produced by the mucous membranes. It functions by protecting the stomach lining and gastric pits from the acid, which is produced by the glands to destroy the bacteria that entered along with the food particles.
Mucous/Mucus
It is the digestive fluid formed by the stomach during the process of digestion. It functions by destroying harmful microorganisms present in the food particles.
Hydrochloric Acid
They are the group of enzymes which functions by breaking down polymeric macromolecules like biopolymers into their smaller and simpler substances.
Digestive Enzymes
Made up of three segments – the duodenum, jejunum, and ileum.
Small Intestine
It is responsible for processing waste so that emptying the bowels is easy and convenient. It’s a 6-foot long muscular tube that connects the small intestine to the rectum.
Large Intestine
Waste products are passed into the end of the large intestine called the ______and eliminated out of the body as a solid matter called stool.
Rectum
Is the last part of the digestive tract. It is a 2-inch long canal consisting of the pelvic floor muscles and the two anal sphincters (internal and external).
Anus
These are organs which participate in the digestion process but are not actually a part of GIT. They stimulate the digestion by releasing certain enzymes that help in breaking down the food.
Accessory Organs
This accessory organ secretes digestive enzymes into the duodenum that break down protein, fats and carbohydrates. The pancreas also makes insulin, passing it directly into the bloodstream. Insulin is the chief hormone in your body for metabolizing sugar.
Pancreas
This accessory organ has many functions, but main job within the digestive system is to process the nutrients absorbed from the small intestine. This accessory organ also secretes bile.
Liver
This accessory organ stores and concentrates bile from the liver, and then releases it into the duodenum in the small intestine to help absorb and digest fats.
Gallbladder
The very first step involves mastication (chewing). The salivary glands, along with the tongue, helps to moisten and lubricate food, before being pushed down into the food pipe.
Ingestion
It involves the process of lubricating and manipulating food and pushing it down the food through the food pipe (using peristalsis), and into the stomach.
Mixing and Movement
The stomach, small intestine, liver, and pancreas secrete enzymes and acids to aid the process of digestion. It functions by breaking down food particles into simple components and easily absorbable components.
Secretion
The process of converting complex food particles into simpler substances in the presence of enzymes and acids secreted by different digestive organs.
Digestion
This process begins in the small intestine where most of the nutrients and minerals are absorbed. The excess water in the indigestible matter is absorbed by the large intestines.
Absorption
The process of removing indigestible substances and waste by-products from the body through the process of defecation.
Excretion
This disease is described as open sores that develop on the inside lining of your stomach and the upper portion of your small intestine. The most common symptom being stomach pain.
Ulcers
Also known as gastroesophageal reflux (GER), is the backward flow of stomach acid into the tube that connects your throat to your stomach (esophagus).
Acid Reflux
Is a common disorder that affects the large intestine. Signs and symptoms include cramping, abdominal pain, bloating, gas, and diarrhea or constipation, or both. It is a chronic condition that you’ll need to manage long term.
Irritable Bowel Syndrome (IBS)
Also called piles, are swollen veins in your anus and lower rectum, similar to varicose veins.
Hemorrhoids
Refers to the series of events that take place in a cell, resulting in the duplication of DNA and division of cytoplasm and organelles to produce two daughter cells.
Cell Cycle
This is the primary stage of the interphase as Diminutive changes are observed due to the hyperactivity of the cell at the biochemical degree.
The cell grows physically larger, copies organelles, and makes the molecular building blocks it will need in later steps.
G1 (Gap 1) Phase
It is an active DNA synthesis and histone synthesis phase of the interphase
The cell synthesizes a complete copy of the DNA in its nucleus. It also duplicates a microtubule organizing structure called the centrosome. The centrosomes help separate DNA during the M phase.
Synthesis (S) phase
This phase is succeeded by the S phase. Here the chromosomes comprise two chromatids thus cell has double the quantity of DNA.
The cell grows more, makes proteins and organelles, and begins to reorganize its contents in preparation for mitosis. It ends when mitosis begins.
G2 (Gap 2) Phase
This phase is succeeded by the G2 phase. Here the cell divides into two daughter cells along with equal distribution of chromosomes between the daughter cells.
The cell divides its copied DNA and cytoplasm to make two new cells.
M (Mitotic) Phase
Is the step in the cell cycle where the newly formed DNA is separated and two new cells are formed with the same number and kind of chromosomes as the parent nucleus.
It is the phase of the cell cycle where the nucleus of a cell is divided into two nuclei with an equal amount of genetic material in both the daughter nuclei.
Mitosis
Immediately follows S and G2 phase of the cycle and is marked by condensation of the genetic material to form compact mitotic chromosomes composed of two chromatids attached at the centromere.
Prophase
This is the phase of the cell cycle in which a typical cell spends most of its life.
Interphase
The nuclear envelop disintegrates. Now the microtubules are allowed to extend from the centromere to the chromosome. The microtubules attach to the kinetochores which allow the cell to move the chromosome around.
Prometaphase
At this stage, the microtubules start pulling the chromosomes with equal force and the chromosome ends up in the middle of the cell. Thus, each cell gets an entire functioning genome.
Metaphase
The splitting of the sister chromatids marks the onset of anaphase. These sister chromatids become the chromosome of the daughter nuclei.
The chromosomes are then pulled towards the pole by the fibers attached to the kinetochores of each chromosome. The centromere of each chromosome leads at the edge while the arms trail behind it.
Anaphase
The chromosomes that cluster at the two poles start coalescing into an undifferentiated mass, as the nuclear envelope starts forming around it. The nucleolus, Golgi bodies and ER complex, which had disappeared after prophase start to reappear.
Telophase
Telophase is followed by ___________, which denotes the division of the cytoplasm to form two daughter cells. Thus, it marks the completion of cell division.
Cytokinesis (Only found in animal cells)
Is the type of cell division that results in four daughter cells, each with half the number of chromosomes of the parent cell.
Meiosis
Homologous chromosomes exchange DNA and the diploid cell is divided into two haploid cells.
Meiosis I
Chromosomes condense and become visible inside the nucleus. As the nuclear envelope begins to break down, homologous chromosomes move closer together.
Prophase I
The key event in ___________ I is the formation of the spindle fiber apparatus where spindle fiber microtubules attach to the kinetochore proteins at the centromeres.
Prometaphase I
The tetrads move to the metaphase plate with kinetochores facing opposite poles.
Metaphase I
The microtubules pull the attached chromosomes apart. The sister chromatids remain tightly bound together at the centromere.
Anaphase I
The separated chromosomes arrive at opposite poles. In some organisms, the chromosomes decondense and nuclear envelopes form around the chromatids.
Telophase I and Cytokinesis
The sister chromatids within the two daughter cells separate, forming four new haploid gametes.
Meiosis II
If the chromosomes decondensed in telophase I, they condense again. If nuclear envelopes were formed, they fragment into vesicles. The centrosomes that were duplicated during interphase I move away from each other toward opposite poles and new spindles are formed.
Prophase II
The nuclear envelopes are completely broken down and the spindle is fully formed. Each sister chromatid forms an individual kinetochore that attaches to microtubules from opposite poles.
Prometaphase II
The sister chromatids are maximally condensed and aligned at the equator of the cell.
Metaphase II
The sister chromatids are pulled apart by the kinetochore microtubules and move toward opposite poles. Non-kinetochore microtubules elongate the cell.
Anaphase II
The chromosomes arrive at opposite poles and begin to decondense. Nuclear envelopes form around the chromosomes. Cytokinesis separates the two cells into four unique haploid cells.
Telophase II and Cytokinesis
Involves one cell division
Results in two daughter cells
Results in diploid daughter cells (chromosome number remains the same as parent cell)
Daughter cells are genetically identical
Occurs in all organisms except viruses
Creates all body cells (somatic) apart from the germ cells (eggs and sperm)
Prophase is much shorter
No recombination/crossing over occurs in prophase.
In metaphase individual chromosomes (pairs of chromatids) line up along the equator.
During anaphase the sister chromatids are separated to opposite poles.
Mitosis
Involves two successive cell divisions
Results in four daughter cells
Results in haploid daughter cells (chromosome number is halved from the parent cell)
Daughter cells are genetically different
Occurs only in animals, plants and fungi
Creates germ cells (eggs and sperm) only
Prophase I takes much longer
Involves recombination/crossing over of chromosomes in prophase I
In metaphase I pairs of chromosomes line up along the equator.
During anaphase I the sister chromatids move together to the same pole.
During anaphase II the sister chromatids are separated to opposite poles.
Meiosis
Why was Pea Plant selected for Mendel’s experiments?
The pea plant can be easily grown and maintained.
They are naturally self-pollinating but can also be cross-pollinated.
It is an annual plant, therefore, many generations can be studied within a short period of time.
It has several contrasting characters.
Mendel conducted 2 main experiments to determine the laws of inheritance. These experiments were:
Monohybrid Cross Experiment,
Dihybrid Cross Experiment
In a heterozygote, the allele which masks the other is referred to as dominant, while the allele that is masked is referred to as recessive. This law states that in a heterozygote, one trait will conceal the presence of another trait for the same characteristic.
Mendel’s Law of Dominance
This law states that a diploid organism passes a randomly selected allele for a trait to its offspring, such that the offspring receives one allele from each parent.
Mendel’s Law of Segregation
This law allows the calculation of genotypic and phenotypic ratios based on the probability of individual gene combinations. This law states that genes do not influence each other with regard to the sorting of alleles into gametes.
Mendel’s Law of Independent Assortment
A __________ cross is one in which both parents are heterozygous (or a hybrid) for a single (mono) trait. The trait might be petal color in pea plants.
Monohybrid Cross
Is a matrix in which all of the possible gametes produced by one parent are listed along one axis, and the gametes from the other parent are listed along the other axis. Each possible combination of gametes is listed at the intersection of each row and column.
Punnett Square
A ________cross is a breeding experiment between two organisms which are identical hybrids for two traits. In other words, a dihybrid cross is a cross between two organisms, with both being heterozygous for two different traits. The individuals in this type of trait are homozygous for a specific trait. These traits are determined by DNA segments called genes.
Dihybrid Cross
A term that describes having two different versions of the same gene
Heterozygous Genotype
A __________ genotype means you inherit two identical alleles.
Homozygous Genotype
