Meiosis, Mutations, Embryology Flashcards

A random change in the sequence of nucleotides in DNA.

Changes that occur within individual genes in a chromosome

type of gene mutation with the deletion or addition of nucleotides resulting in disruption of codon sequence

type of gene mutation when one base is substituted with another letter

Changes in the structure of a chromosome

Chromosome breaks and a piece of chromosome is lost OR when bases are removed

Part of a chromosome breaks off and is incorporated into its homologous chromosome

A part of chromosome breaks off and attaches to a different, non-homologous chromosome

The entire base sequence of all the DNA in an organism

When a part of a chromosome breaks off, turns around (flips), and reattaches in the reverse order

A photograph of all organism's chromosomes

Failure of chromosomes to separate during cell division; causes monosomy and trisomy in sex cells

The zygote has only ONE copy of a particular chromosome

The zygote has THREE copies of the chromosome

a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.

The hollow ball of cells marking the end stage of cleavage (second embryo stage)

an embryo at the stage following the blastula, when it is a hollow cup-shaped structure having three layers of cells. (third embryo stage)

A solid ball of cells that makes up an embryo; in humans, this stage occurs within four days of fertilization. (first embryo stage)

the developing human organism from about 2 weeks after fertilization through the second month

study of embryos and their development

trisomy of chromosome 13; in babies - cleft lips, polydactyly, rocker bottom feet, heart issues...

trisomy of chromosome 21; affects facial features and intellectual ability

A chromosomal disorder in which males have an extra X chromosome, making them XXY instead of XY.

trisomy of chromosome 18; in babies - low-set ears, overlapping fingers, rocker bottom feet, heart issues...

A chromosomal disorder in females in which either an X chromosome is missing, making them

a partial deletion in chromosome 5 that results in children who are mentally disabled, have small heads, and have a cry that sounds like a loud cat

Two babies born physically connected to each other

twins who develop from separate fertilized eggs.

twins who develop from a single fertilized egg that splits in two

when homologous chromosomes pair up and form tetrads (synapsis) and then crossing over occurs, assorted independently of each other

when tetrads (homologous chromosomes) are lined up next to each other at the equator; X's are on top of each other

when X's are lined up next to each other at the equator; chromatids are on top of each other

when tetrads (homologous chromosomes) split up and X's head to opposite poles

when the X splits up and sister chromatids move to opposite poles

the pairing of homologous chromosomes during prophase I of meiosis

the exchanging of genes between homologous chromosomes; genetic recombination event #1

Mendel's 2nd law, stating that allele pairs separate from one another during gamete formation (prophase I crossing over has each gene exchanging independently of each other, then anaphase I they split up into separate gametes)

Mendel's 1st law that states that the pairs of homologous chromosomes separate in anaphase I of meiosis so that only one chromosome from each pair is present in each gamete

site of crossing over

structure containing 4 chromatids = 2 X's = a pair of homologous chromosomes; formed in synapsis

Egg production via meiosis

production of sperm via meiosis

human egg

Process in sexual reproduction in which male and female reproductive cells join to form a new cell

Cells produced in females in meiosis that do not participate in reproduction

an immature male sex cell

where meiosis occurs

haploid, human gametes (sex cells)

plural form of ovumov