Sexual Reproduction

Question 1

Holt-oram syndrome

Answer 1

Heart and hand defect that causes atrial separation and a range of hand abnormalities

Question 2

Process of egg activation

Answer 2

Sperm and egg membranes fuse, sperm disconnects from its flagellum, male pronucleus migrates towards female pronucleus, fusion forms diploid nucleus

Question 3

The embryo undergoes cleavage to…

Answer 3

Convert the large cytoplasmic mass into blastomeres (small, maneuverable cells)

Question 4

Genetic sex determination is controlled by…

Answer 4

SRY

Question 5

SRY (sex determining region Y)

Answer 5

Gene on Y chromosome that encodes for a transcription factor that induces male testicular development, and induces expression of Sox9 which drives male development

Question 6

Costs of sexual reproduction

Answer 6

Maintaining molecular machinery, finding a mating partner, decreased reproductive capacity

Question 7

Benefits of sexual reproduction

Answer 7

High genetic variability (aids evolution), brings together advantageous alleles (resistance to pathogens), masking of deleterious mutations

Question 8

Male germ cell

Answer 8

Sperm of spermatozoa

Question 9

Female germ cell

Answer 9

Secondary oocyte

Question 10

Meiosis

Answer 10

Leads to haploid number of chromosomes, ensuring no two offspring of parents are genetically identical

Question 11

Meiosis 1

Answer 11

Separation of homologous chromosomes, genetic cross-over

Question 12

Meiosis 2

Answer 12

Separation of paired chromatids (similar to mitosis)

Question 13

Chromatid exchange (crossing over)

Answer 13

Chromosomes frequently exchange parts of their DNA, leading to recombinant chromatids containing a mix of DNA from both homologues

Question 14

Cross-over

Answer 14

Results in incomplete linkage of genes on the same chromosome, meaning alleles on the same chromosome are not always inherited together

Question 15

Genetic map

Answer 15

Based on recombination frequency, representation of gene locations on a chromosome

Question 16

Linkage

Answer 16

Genes located close together on a chromosome are considered linked and have lower recombination frequency

Question 17

Alfred sturtevant

Answer 17

Pioneer of genetic mapping, first proposed use of recombination frequency in mapping

Question 18

X-linked inheritance

Answer 18

Pattern of generic inheritance that occurs when a gene variant is located on the x-chromosome

Question 19

Autosomal chromosome aneuploidy

Answer 19

Down syndrome, Edwards syndrome, Patau syndrome

Question 20

Sex chromosome aneuploidy

Answer 20

Klinefelter syndrome, XYY syndrome, triple X syndrome, Turner syndrome