IB Biology Topic D3.2.11 Sex Determination in Humans and Inheritance of Genes on Sex Chromosomes Revision Notes (SL/HL)

IB Biology Topic D3.2.11 Sex Determination in Humans and Inheritance of Genes on Sex Chromosomes Revision Notes (SL/HL) | RevisionDojo

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Sex Is Determined by the X and Y Chromosomes

Humans have 23 pairs of chromosomes, and the 23rd pair determines sex.
1. Females have two X chromosomes (XX), carrying about 900 genes.
2. Males have one X and one Y chromosome (XY).
3. The Y chromosome is much smaller, carrying only about 55 genes, most tied to male development.

The Sperm Decides the Sex of the Offspring

The egg always carries an X chromosome, so the sperm decides the sex of the zygote.
1. An X-carrying sperm produces an XX (female) zygote.
2. A Y-carrying sperm produces an XY (male) zygote.
The SRY gene on the Y chromosome acts as a switch that triggers the testes to form.

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Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
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Sex Is Determined by the X and Y Chromosomes

Humans have 23 pairs of chromosomes, and the 23rd pair determines sex.
1. Females have two X chromosomes (XX), carrying about 900 genes.
2. Males have one X and one Y chromosome (XY).
3. The Y chromosome is much smaller, carrying only about 55 genes, most tied to male development.

The Sperm Decides the Sex of the Offspring

The egg always carries an X chromosome, so the sperm decides the sex of the zygote.
1. An X-carrying sperm produces an XX (female) zygote.
2. A Y-carrying sperm produces an XY (male) zygote.
The SRY gene on the Y chromosome acts as a switch that triggers the testes to form.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic D3.2.11: Sex Determination in Humans and Inheritance of Genes on Sex Chromosomes Notes

Sex Is Determined by the X and Y Chromosomes

The Sperm Decides the Sex of the Offspring

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Sex Is Determined by the X and Y Chromosomes

The Sperm Decides the Sex of the Offspring

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics