The stomach releases acids and juices, which further break down food into a thick, pasty material called chyme.
Many scientists believe a meteorite struck Earth over 65 million years ago and is responsible for altering Earth's weather, which led to the extinction of dinosaurs and other life.
An extra photosynthetic pathway, called the "C4 pathway," acts as a carbon dioxide pump that provides more fixed carbon to the Calvin cycle. This allows C4 plants to fix CO2 more rapidly, thus producing more glucose.
To prevent water loss, they close their stomates during the day. This inhibits the entry of carbon dioxide. To compensate, they take in CO2 during the night when stomates are open.
Carbon fixation takes place via a series of complex reactions collectively referred to as the "Calvin cycle." The starting and ending point in the Calvin cycle is a 5-carbon sugar called "ribulose bisphosphate," or RuBP for short.
Light-dependent reactions occur in areas of the thylakoid referred to as "photosystems." There are two different types of photosystems called "photosystem I" and "photosystem II."
Plants possess vascular tissue, which is a system of tiny tubes that move food and water throughout the plant.
Once a seed has made its home in the soil, its next step is to begin germination. But germination does not always occur right away. Seeds may remain dormant in the soil anywhere from a few weeks to many years.
Above the point of attachment of the cotyledons is a structure called the "epicotyl." Later, it gives rise to the upper part of the stem, the leaves, and the terminal bud.
In the sexual reproduction of ferns, spores are released into the air and eventually fall to the ground to form a prothallus in the gametophyte phase. The gametophyte produces eggs and sperm. The sperm swims to the egg and fertilization occurs.
Underneath the bark of a tree is a layer of phloem, which consists of tubular cells that move food from the leaves and stem throughout the body of the plant. Cambium, another type of vascular tissue, is responsible for making new xylem and phloem.
The blastocyst becomes embedded in the wall of the uterus in a process called "implantation." This signifies the beginning of pregnancy. Following implantation, the blastocyst further develops into a three-layered structure, the gastrula.
Let's begin at day one, when the pituitary glands release two hormones-- follicle-stimulating hormone, or FSH for short, and luteinizing hormone, or LH. FSH stimulates a follicle to develop into an egg.
The egg then travels through the oviduct, also called the "fallopian tube." If fertilization occurs, it happens here. Then, the egg travels to the thick-walled, muscular uterus.
When the egg sac matures, its follicle moves to the surface of the ovary, breaks open, and releases the egg.
The two vas deferens empty to the urethra, the same structure through which urine empties. As sperm enter the urethra, the seminal vesicles, Cowper's glands, and the prostate gland secrete fluids into the urethra that nourishes and protects sperm.
Per Utah Code 53G-10-402 parental consent is required prior to teaching this material.
Sperm cells are produced in the seminiferous tubules but then move to the epididymis where they mature and are stored. Mature sperm exit the epididymis through a tube called the "vas deferens."
It's in the uterus that the fetus develops. At the bottom of the uterus is the cervix. That's the opening into the vagina, which leads to the outside of the body.
The zygote then slowly moves through the fallopian tube as it gradually undergoes a series of cell divisions referred to as "cleavage." In the process of cleavage, the zygote repeatedly divides and develops into a ball of cells called a "morula."
Small bronchioles end in tiny air sacs call "alveoli," arranged kind of like grapes on a stem. Alveoli consist of thin membranes lined with a dense network of capillaries across which gas exchange occurs with blood cells.