5.1-2: Intro to Heredity (excluding meiosis)

Question 1

What are genetics?

Answer 1

• the study of heredity and hereditary variation

Question 2

What is heredity?

Answer 2

• The transmission of traits from one generation to the next

Question 3

We know that heredity is the transmission of traits to the next generation. How does this occur? (3)

Answer 3

• traits are passed from parent to offspring through genes
• segments of DNA that code for basic units of heredity
• offspring acquire genes from parents by inheriting chromosomes

Question 4

What are the characteristics of asexual reproduction? (5)

Answer 4

1. Single individual
2. no fusion of gametes
3. clones are offspring that are exact copies of parents
4. Mutations are the only source of variation
5. can produce asexually through mitosis

Question 5

What are the characteristics of sexual reproduction? (3)

Answer 5

• two parents (male/female)
• Offspring are unique combinations of genes from parents
• Genetically varied from parents and siblings

Question 6

What are homologous chromosomes? Who are they inherited from?

Answer 6

• a pair of chromosomes (same size, length, centromere, position) that carry the same genetic information
• One homologous chromosome is inherited from mom and one is inherited from dad

Question 7

What are karyotypes? (2)

Answer 7

• A display of chromosome pairs ordered by size and length
  Note: in actual karyotypes it is difficult to see the sister chromatids in each pair
• see diagram on page 5

Question 8

How do you read karyotypes? (3)

Answer 8

• grouped in pairs and numbers
• the pair represents homologous xmes
• numbers represent relative size and shape of xmes

Question 9

What is the most common type of chromosomal abnormality seen on karyotypes?

Answer 9

• aneuploidy, or abnormal chromosome number

- see chart of page 7 for abnormalities

Question 10

What are somatic (body) cells in terms of chromosomes?

Answer 10

• diploid or 2n
• two complete sets of each chromosome
• humans: 2n=46

Question 11

What are gametic (sex) cells in terms of chromosomes? (4)

Answer 11

• haploid or n
• one set of xmes
• humans (sperm or eggs)
  n= 23

Question 12

All eukaryotes have ___ that is packaged in ___

Answer 12

DNA, chromosomes

Question 13

What are the two types of chromosomes?

Answer 13

Autosomes and sex chromosomes

Question 14

What are autosomes? how many pairs do humans have?

Answer 14

• chromosomes that do not determine sex

- humans have 22 pairs

Question 15

What are included in sex chromosomes? (3)

Answer 15

• X and Y
• eggs: X (humans 22+x)
• sperm X or Y humans 22+x or 22+Y)

Question 16

What is the life cycle?

Answer 16

• sequence of stages in the reproductive history of an organism from conception to its own reproduction

Question 17

___ and ____ alternate in sexual life cycles

Answer 17

• fertilization and meiosis

Question 18

What occurs in fertilization?

Answer 18

• a sperm cell (haploid) fuses with an egg (haploid) to form a zygote (diploid)