Heredity/Mendelian Genetics

Question 1

How is metaphase I of meiosis different from metaphase of Mitosis?

Answer 1

In metaphase I of meiosis, chromosome pairs line up together. In mitosis, single chromosomes line up one by one.

Question 2

What are the stages of meiosis and how do they compare to Mitosis?

Answer 2

Meiosis has two rounds of cell division (Meiosis I and II), each with prophase, metaphase, anaphase, and telophase, creating four unique haploid cells, while mitosis has one round with the same stages but produces two identical diploid cells.

Question 3

What are homologous chromosomes and how many do humans and fruit flies have?

Answer 3

Homologous chromosomes are a pair of chromosomes, one from each parent, that have the same genes. humans have 23 pairs; fruit flies have 4 pairs.

Question 4

What is crossing over and when does it occur?

Answer 4

Crossing over swaps DNA between homologous chromosomes in prophase I; increases genetic diversity.

Question 5

How many male gametes are formed from one spermatocyte?

Answer 5

Four sperm from one spermatocyte.

Question 6

How many female gametes are formed from one oocyte and how many polar bodies are created?

Answer 6

One egg and three polar bodies from one oocyte.

Question 7

What is the only immortal cell humans have?

Answer 7

Egg cells are the only immortal human cells.

Question 8

How do we differentiate males from females in plants and animals based on cell type and motility?

Answer 8

Males make small, motile gametes; females make large, non-motile ones.

Question 9

How many autosomes do humans have and what are the sex chromosomes?

Answer 9

Humans have 44 autosomes; sex chromosomes are X and Y.

Question 10

What are bird sex chromosomes?

Answer 10

Birds use Z and W.

Question 11

What is a Karyotype?

Answer 11

A karyotype is a picture of all the chromosomes in a cell, arranged by size and shape. It helps check for chromosome problems.

Question 12

What are the steps to create a karyotype for a human?

Answer 12

Collect cells, stop division, stain, photograph, arrange.

Question 13

What type of disorders are karyotypes used to diagnose?

Answer 13

Karyotypes diagnose chromosomal disorders like Down syndrome.

Question 14

How many chromosomes do all non-human primates have?

Answer 14

Non-human primates have 48 chromosomes.

Question 15

Why do humans have 2 fewer chromosomes than non-human primates?

Answer 15

Humans have 46 due to fusion of two ancestral chromosomes.

Question 16

What does a female calico cat tell us about the X chromosomes in a female?

Answer 16

Calico cats show X-inactivation; each cell expresses one X randomly.

Question 17

What is the key gene on the Y chromosome that is not found on the X chromosome?

Answer 17

SRY gene determines male sex and is only on Y chromosome.

Question 18

How does chromosome number determine sex in bees?

Answer 18

In bees, females develop from fertilized eggs and are diploid; males develop from unfertilized eggs and are haploid.

Question 19

What determines sex in turtles?

Answer 19

Turtle sex depends on temperature during egg incubation.

Question 20

Who is the father of genetics?

Answer 20

Gregor Mendel is the father of genetics.

Question 21

What organism did Gregor Mendel study?

Answer 21

He studied pea plants.

Question 22

What are the male parts of a flower?

Answer 22

Male flower parts: anther and filament (stamen).

Question 23

What are the female parts of a flower?

Answer 23

Female flower parts: stigma, style, ovary (carpel).

Question 24

What enlarges into a fruit?

Answer 24

Ovary enlarges into fruit.

Question 25

What do we call a fertilized egg that develops inside the fruit?

Answer 25

Fertilized egg is a zygote.

Question 26

What are the three types of plants that came before flowering plants?

Answer 26

Mosses, ferns, and gymnosperms.

Question 27

What is Mendel's first law?

Answer 27

Mendel's first law, the Law of Segregation, says each parent gives just one of their two genes to their child.

Question 28

What experiment did Mendel do that no one else thought to do?

Answer 28

He tracked traits through F1 and F2 generations to reveal patterns.

Question 29

What is the famous phenotype ratio observed in the offspring when two heterozygous individuals are crossed for one trait?

Answer 29

3:1 phenotype ratio for monohybrid heterozygous cross.

Question 30

What is Mendel's second law?

Answer 30

Mendel’s second law, the law of Independent assortment, says traits are passed down independently.

Question 31

What is the famous phenotype ratio observed in the offspring when crossing two heterozygous individuals for two traits?

Answer 31

9:3:3:1 phenotype ratio in dihybrid heterozygous cross.

Question 32

How many different ways can 23 pairs of chromosomes assort?

Answer 32

2²³ = over 8 million combinations from independent assortment.

Question 33

What is nondisjunction?

Answer 33

Nondisjunction is failed chromosome separation.

Question 34

What condition does nondisjunction of chromosome 21 cause?

Answer 34

Causes Down syndrome with chromosome 21.

Question 35

What is an allele?

Answer 35

An allele is a version of a gene.

Question 36

How many alleles do you have for one gene?

Answer 36

You have two alleles for each gene, one from each parent.

Question 37

Distinguish between dominant and recessive genes.

Answer 37

Dominant genes show their trait even if there's only one copy; recessive genes need two copies to show.

Question 38

Distinguish between homozygous and heterozygous.

Answer 38

Homozygous means two of the same alleles, heterozygous means two different ones.

Question 39

Distinguish between 1N/2N, Diploid/Haploid/Polyploid.

Answer 39

1N means one set of chromosomes (haploid), 2N means two sets (diploid). Polyploid means more than two sets.

Question 40

What types of Punnett squares should you be able to do?

Answer 40

Monohybrid, dihybrid, sex-linked, blood type, codominant, incomplete dominance.

Question 41

Why are males at a disadvantage for genes on the X-chromosome?

Answer 41

Males have only one X chromosome, so one bad gene shows up immediately.

Question 42

What sex-linked condition was spread through the Houses of Europe originating with Queen Victoria?

Answer 42

Hemophilia was passed through royal families from Queen Victoria.

Question 43

What would we call Queen Victoria since she had the gene for hemophilia but no symptoms?

Answer 43

She was a carrier.

Question 44

Know the three alleles in the population for blood type.

Answer 44

The three blood type alleles are A, B, and O.

Question 45

How many possible gametes can a dihybrid cross produce?

Answer 45

A dihybrid cross can make 4 different gametes.

Question 46

How many possible gametes can a trihybrid cross produce?

Answer 46

A trihybrid cross can make 8 different gametes.

Question 47

Distinguish codominance from incomplete dominance in terms of phenotypes.

Answer 47

In codominance, both traits show up fully; in incomplete dominance, the traits blend together.

Question 48

By what type of selection has teosinte changed into modern corn?

Answer 48

Teosinte became modern corn through artificial selection.

Question 49

What is pleiotropy?

Answer 49

Pleiotropy occurs when one gene affects multiple traits.

Question 50

Give one example of pleiotropy.

Answer 50

The gene responsible for sickle cell anemia affects red blood cells, oxygen transport, and can also cause pain and organ damage.

Question 51

What is polygenic inheritance?

Answer 51

Polygenic inheritance means many genes work together to affect one trait.

Question 52

Give one example of polygenic inheritance.

Answer 52

Height is a common example.

Question 53

How many genes code for skin color?

Answer 53

Skin color is controlled by about 169 genes.

Question 54

How many genes affect eye color?

Answer 54

Eye color is affected by 16 genes.

Question 55

What does epistasis mean?

Answer 55

Epistasis is when one gene can hide or change the effect of another.

Question 56

Give an example of epistasis.

Answer 56

In labs, one gene decides color, another decides if color shows.

Question 57

What is the nature vs nurture concept?

Answer 57

Environment can change how genes work.

Question 58

Give an example how the environment can override genetics in an organism's phenotype.

Answer 58

In Labrador retrievers, one gene controls coat color, but another gene can block the color entirely.

Question 59

What is a pedigree?

Answer 59

A pedigree is a chart showing family traits.

Question 60

How are males and females distinguished in a pedigree?

Answer 60

Circles are females, squares are males, and lines connect parents to children.