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Генетика (194)

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EN_01314036_0250
EN_01314036_0250

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.

EN_01314036_0251
EN_01314036_0251

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.

EN_01314036_0252
EN_01314036_0252

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.

EN_01314036_0253
EN_01314036_0253

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.

EN_01314036_0254
EN_01314036_0254

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.

EN_01314036_0255
EN_01314036_0255

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.

EN_01314036_0256
EN_01314036_0256

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.

EN_01314036_0272
EN_01314036_0272

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.

EN_01314036_0273
EN_01314036_0273

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.

EN_00966138_0001
EN_00966138_0001

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.

EN_00966278_2761
EN_00966278_2761

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.

EN_00966278_2764
EN_00966278_2764

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.

EN_00966278_2768
EN_00966278_2768

Illustration of the cell cycle. Each stage is defined by changes in the cell as chromosomal replication and other metabolic activities proceed during mitosis. The various stages present discrete targeting opportunities in cancer therapy.

EN_00966278_2769
EN_00966278_2769

Illustration of the cell cycle. Each stage is defined by changes in the cell as chromosomal replication and other metabolic activities proceed during mitosis. The various stages present discrete targeting opportunities in cancer therapy.

EN_00966278_3565
EN_00966278_3565

Conceptual photocomposite of genetics, showing a silhouetted man standing below a strand of DNA and a face in the background.

EN_00966278_4064
EN_00966278_4064

Illustration of body movement during exercise showing a woman stepping in phase with her skeleton.

EN_00966278_4065
EN_00966278_4065

Illustration of body movement during exercise showing a woman stepping in phase with her skeleton.

EN_00966278_4066
EN_00966278_4066

Illustration of a woman exercising, with dual reflections.

EN_00966278_4067
EN_00966278_4067

Illustration of a woman exercising, with dual reflections.

EN_00966278_4145
EN_00966278_4145

Illustration of a hand holding a glowing test tube, the concept of a scientific breakthrough.

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