Notes, abstracts, papers, exams and problems of Biology

Characteristics of Poriferans

Poriferans, also called sponges, are aquatic organisms (the majority of them are marine organisms) that either have no symmetry or have radial symmetry. Their bodies, which have a tube shape, a cup shape, or an irregular shape, have multiple pores that are interlinked by thin channels. These channels lead to a central cavity, called the atrium, which is linked to the outside by an opening called the osculum. Inside the channels, there are cells known as choanocytes, which are specialized in capturing food.

Poriferans stay upright due to a skeleton made of small spines called spicules. They feed by filtration. Water, which contains food particles, enters through the pores and exits through the osculum with the food... Continue reading "Characteristics of Poriferans: Aquatic Organisms with Unique Structures and Reproduction" »

hormones-chemicals produced by special cells  

hypothalamus-part of the vertebral brain connects endo./nerv. Syst

hypothalamus

posterior pituitary gland         cerebrum-lagest part of the brain

anterior pituitary gland           CNS-consists of the brain and spinal cord

thyroid gland                         PNS-nerve receptors and endings

parathyroid gland

pancreas-consists of langerhans

homeostasis-normal functioning condition of human body

embryos-developing individuals from insemination to birth

male gonads-testis

female gonads-ovaries

gene-code messages that relays information

DNA deoxyribonucleic acid-AKA building blocks of life

amino acid-component of ribosomes that forms polypeptides

mRNA-conveys genetic... Continue reading "Marchantia male" »

1)Which of the following best describes a karyotype?

·a display of each of the chromosomes of a single cell

2) The human X and Y chromosomes

·include genes that determine an individual's sex.

3) Which of the following is true of a species that has a chromosome number of 2n = 16?

·Each cell has eight homologous pairs.

4) In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common?

·Length, centromere position, staining pattern, and traits coded for by their genes.

5) Meiosis II is similar to mitosis in that

·sister chromatids separate during anaphase

6) Which of the following occurs in meiosis but not in mitosis?

·synapsis of... Continue reading "Understanding Genetics: Karyotypes, Meiosis, and Inheritance" »

Difference between primary and secondary sex characteristics:

The primary are the sexual organs which are born with and the secondary are the physical characteristics developed during puberty

Reproduction:

Reproduction is the creation of new individuals

Explain the journey of sperm to the ovum:

After being secreted by the penis through the urethra, the sperm go from the vagina to the uterus. Then, they divide into 2 groups and go to each fallopian tube. If there’s an ovum, one of these single sperm will fertilize it, and they will form a zygote, divide and become a morula and later a blastocyst. On the 7th day, the blastocyst implants in the endometrium

Structure:

NUMERO QUATTRO: HT Family History

Contains the health condition of parents (grandparents), siblings and children of the patient; no wife/husband. Have to note the occurrence of inheritable diseases: haemophilia, spherocytosis, DM, hypertension, cancer, “obesity”?. Draw family tree and mark affected people, we can localize if the disease is dominant, recessive and linked to sex chromosome X. Examination of chest.

INSPECTION:

SHAPE: Barrel chest (expiration prolonged, difficult), Pigeon breast (protruding breast bone, common in rickets), Funnel breast (inward deformity of sternum), Kyphoscoliosis (curvature of the spine, common in childhood rickets, can compromise ventilation), general deformities (due to chronic pulmonary and pleural diseases... Continue reading "Family History, Chest Examination, and Cardiac Diseases" »

Hyperadrenalism:

3-carbon dioxide concentration

Cell Theory

Cells are the basic unit of life, all organisms are made up of 1 or more cells, and all cells arise from existing cells.

Contributors to Cell Theory

Hooke

Robert Hooke, a British scientist, first named cells in 1665. He observed cork with a microscope.

Scheiden

Matthias Jakob Schleiden, a German botanist, concluded that plants were made of cells.

Schwann

Theodor Schwann, a German zoologist, found that all living things are made of cells.

Leeuwenhoek

Antonie van Leeuwenhoek, a Dutch fabric store owner, ground a lens that magnified the microscope 200x's.

Virchow

Rudolf Virchow, a German doctor, disputed the idea of spontaneous generation (the idea that cells come from nothing) and concluded that cells come from other cells.

Cell Structures

Cell