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Sperm fertilizing egg, computer illustration. The sperm has an oval head and a hair-like tail which it beats with a whiplash motion to swim. The human female usually produces a single large egg from the ovary, while the male releases some 300 million much smaller sperm. The sperm travel through the uterus (womb) and up the fallopian tubes to reach the egg. The sperm must penetrate a thick layer around the egg; this penetration is aided by enzymes contained in the sperm's head. Only one sperm can fuse with the egg nucleus. Fertilisation enables male and female genetic material to be shared.
Sperm fertilizing egg, computer illustration. The sperm has an oval head and a hair-like tail which it beats with a whiplash motion to swim. The human female usually produces a single large egg from the ovary, while the male releases some 300 million much smaller sperm. The sperm travel through the uterus (womb) and up the fallopian tubes to reach the egg. The sperm must penetrate a thick layer around the egg; this penetration is aided by enzymes contained in the sperm's head. Only one sperm can fuse with the egg nucleus. Fertilisation enables male and female genetic material to be shared.
Sperm fertilizing egg, computer illustration. The sperm has an oval head and a hair-like tail which it beats with a whiplash motion to swim. The human female usually produces a single large egg from the ovary, while the male releases some 300 million much smaller sperm. The sperm travel through the uterus (womb) and up the fallopian tubes to reach the egg. The sperm must penetrate a thick layer around the egg; this penetration is aided by enzymes contained in the sperm's head. Only one sperm can fuse with the egg nucleus. Fertilisation enables male and female genetic material to be shared.
Sperm fertilizing egg, computer illustration. The sperm has an oval head and a hair-like tail which it beats with a whiplash motion to swim. The human female usually produces a single large egg from the ovary, while the male releases some 300 million much smaller sperm. The sperm travel through the uterus (womb) and up the fallopian tubes to reach the egg. The sperm must penetrate a thick layer around the egg; this penetration is aided by enzymes contained in the sperm's head. Only one sperm can fuse with the egg nucleus. Fertilisation enables male and female genetic material to be shared.
Sperm fertilizing egg, computer illustration. The sperm has an oval head and a hair-like tail which it beats with a whiplash motion to swim. The human female usually produces a single large egg from the ovary, while the male releases some 300 million much smaller sperm. The sperm travel through the uterus (womb) and up the fallopian tubes to reach the egg. The sperm must penetrate a thick layer around the egg; this penetration is aided by enzymes contained in the sperm's head. Only one sperm can fuse with the egg nucleus. Fertilisation enables male and female genetic material to be shared.
Human ovum, or egg, surrounded by numerous spermatozoa, computer illustration. In fertilisation, only a single sperm may successfully penetrate the ovum to fuse with the female nucleus. Barriers to be overcome include layers of follicular cells surrounding the ovum (corona radiata) and an underlying glycoprotein membrane, the zona pellucida. The membrane is digested by enzymes released from the acrosome, a cap on the head of the sperm: subsequent rapid chemical changes in the zona pellucida prevent competing sperm from entering.
Human ovum, or egg, surrounded by numerous spermatozoa, computer illustration. In fertilisation, only a single sperm may successfully penetrate the ovum to fuse with the female nucleus. Barriers to be overcome include layers of follicular cells surrounding the ovum (corona radiata) and an underlying glycoprotein membrane, the zona pellucida. The membrane is digested by enzymes released from the acrosome, a cap on the head of the sperm: subsequent rapid chemical changes in the zona pellucida prevent competing sperm from entering.
Human ovum, or egg, surrounded by numerous spermatozoa, computer illustration. In fertilisation, only a single sperm may successfully penetrate the ovum to fuse with the female nucleus. Barriers to be overcome include layers of follicular cells surrounding the ovum (corona radiata) and an underlying glycoprotein membrane, the zona pellucida. The membrane is digested by enzymes released from the acrosome, a cap on the head of the sperm: subsequent rapid chemical changes in the zona pellucida prevent competing sperm from entering.
Human ovum, or egg, surrounded by numerous spermatozoa, computer illustration. In fertilisation, only a single sperm may successfully penetrate the ovum to fuse with the female nucleus. Barriers to be overcome include layers of follicular cells surrounding the ovum (corona radiata) and an underlying glycoprotein membrane, the zona pellucida. The membrane is digested by enzymes released from the acrosome, a cap on the head of the sperm: subsequent rapid chemical changes in the zona pellucida prevent competing sperm from entering.
Illustration of amniocentesis, in which a sample of amniotic fluid is removed and tested to detect fetal age and sex, chromosome abnormalities (a chart of normal female chromosomes is shown, top right), neural tube defects, inherited diseases, and fetal Rh factor sensitization. Risks include infection, membrane rupture, fetal injury, and premature labor.
Conceptual image of a DNA chip matching pieces of DNA to complementary strands in an array of incrementally varied DNA samples embedded on silicon. This is done to identify specific nucleotide sequences that can be linked to cancer traits, e.g., virulence, metastatic potential, or susceptibility to bioengineered drugs, to create individual cancer treatments.
Illustration of various of biomarkers. These include mitochondrial DNA, bloodborne viral particles, single nucleotide polymorphisms (SNP's, or snips), nuclear debris from apoptotic cells, tyrosine kinase receptors, and other metabolic pathway proteins. They are used to track down cancers and identify processes vulnerable to therapeutic intervention.