Patterns of Chromosome Inheritance

Question 1

Chromatin

Answer 1

A collection of DNA and protein

The primary function is to package long DNA molecules into more compact, denser structures.

Question 2

Chromosomes

Answer 2

Structures that assist in the transmission of genetic information from one generation to the next

Question 3

Sister Chromatid

Answer 3

• The two identical parts that compose a chromosome

- The first and second copy of a chromosome

Question 4

Centromere

Answer 4

Holds the chromatids together until a specific phase in mitosis when it then splits

Question 5

Duplicated Chromosome

Answer 5

A copied chromosome

Question 6

Unduplicated chromosomes

Answer 6

Unduplicated chromosomes are single linear strands, whereas duplicated chromosomes contain two identical copies (called chromatids or sister chromatids) joined by a centromere.

Question 7

Homologous chromosome

Answer 7

• Members of a pair of chromosomes

- They look alike and carry genes for the same traits

Question 8

Diploid

Answer 8

• 2(n)

- 2 complete sets of chromosomes, one from each parent

Question 9

Haploid

Answer 9

• 1(n)
• # of chromosomes
• Cell/nucleus that contains a single set of unpaired chromosome

Question 10

Gene vs Allele

Answer 10

Gene is what it codes for

Allele is the specific variety

Question 11

of chromosomes in a human cell

Answer 11

46

Question 12

of chromosomes in a gamete

Answer 12

-23

Question 13

Autosomes

Answer 13

• Chromosomes other than sex chromsomes

- 44

Question 14

Sex chromosomes

Answer 14

• The chromosomes that determine our gender

- We have 2

Question 15

Interphase

Answer 15

• The time when organelles in the cell go perform their normal functions (and eventually gets ready to divide)
• Divided into 3 main phases (G1, [doubles organelles and accumulates materials needed for DNA sythesis] S, [A copy is made of all the DNA in the cell. DNA replication occurs] and G2 [The cell makes the proteins needed for cell division])

Question 16

Mitosis

Answer 16

• Type of nuclear division
• 2 stages (prophase [centromeres outside the nucleus have duplicated and begin to move away from each other, The nuclear envelope begins to fragment, Nucleus disapears], metaphase [spindle is fully form, chromosomes attached to the spindle fibers line up at the metaphase plate during metaphase], anaphase [chromosomes move towards opposite poles of the spindle to ensure that each cell receives a copy of each type of chromosome and thereby has a full complement of genes], telophase [chromosomes arrive at poles, spindle disappears, nuclear envelope components reassemble in each cell)
• Somatic cells, adult stem cells, and the cells in the embryo undergo mitosis
• New cells are daughter cells

Question 17

Meiosis

Answer 17

• Gametes undergo meiosis
• 4 daughter cells as end result
• 2 consecutive cell divisions
• There are six phases in meiosis 1
• There are 3 phases in meiosis 2

Phases of Meiosis 1
Prophase 1- Homologous chromosomes pair during synapse allowing for crossing over to occur
Metaphase 1- Independent assortment occurs as homologous chromosomes pair along the metaphase plate
Anaphase 1- Homologous chromosomes separate, pulled to opposite poles by centromeric spindle fibers
Telophase 1- Daughter cells have one chromosome from each homologous pair
Interkinesis- Chromosomes still consist of two chromatids

Phases of Meiosis 2
Prophase 2- Cells hav eone chromosome from each homologus pair
Metaphase 2- Chromosomes align at tge metaphase plate
Anaphase 2- Daughter chromosomes move toward the poles
Telophase 2- Spindle disappearsm nuclei form and cytokinesis takes place

In the end you are left with daughter cells

Question 18

Why are haploid (versus diploid) cells produced during meiosis?

Answer 18

Haploid cells are produced during meiosis (vs diploid) because the zygote formed by two gametes ideally has the same amount of chromosomes as their parents. This is necessary for fertilization.

Question 19

Differences of mitosis and meiosis

Answer 19

Meiosis= reduction division
Mitosis= duplication division

Question 20

Crossing over

Answer 20

• Advantage is that no two gametes are alike (if they were then there would be very little variation in the world)
• Occurs after Independent assortment
• Homologous chromosomes find each other and swap genetic material

Question 21

Independent assortment

Answer 21

• Independent division of chromosomes resulting in gametes

- Random

Question 22

Karayotype

Answer 22

• A computer arrangement of the chromosomes in pairs

Question 23

Aneuploidy

Answer 23

Having either not enough or too many chromosomes

Question 24

Nondisjunction

Answer 24

• An abnormal separation of chromosomes

- Can happen during miosis 1 or miosis 2

Question 25

Trisomy

Answer 25

- The result of when an egg with 24 chromosomes is fertilized with a normal sperm - Down syndrome

Question 26

Monosomy

Answer 26

- The result of when an egg with 22 chromosomes is fertilized with normal sperm, the result is called monosomy, because one type of chromosome is presented in a single copy (2n-1)

Question 27

What are the four types of changes in chromosomes that can occur?

Answer 27

- Deletion, duplication, inversion, and translocation

Question 28

Poly-genetic inheritance

Answer 28

- multiple genes involved - possibly multiple chromosomes involved - effects are additive - results in continuous variation

Question 29

Autosomal Dominant Genes

Answer 29

The genes for autosomal dominant genes are found on one of the 22 autosomes in the cell. The genes are considered dominant because only one copy of the gene needs to be inherited in order to express the dominant trait.

Question 30

Autosomal recessive genes

Answer 30

found on one of the 22 autosomes. The genes are considered recessive because two copies of the gene must be inherited in order to express the recessive trait.

Question 31

X linked recessive

Answer 31

X-linked recessive genes are found on the X chromosome. In females, both copies of the recessive gene need to be inherited in order for her to express the recessive trait. Since males only have one X to begin with, they only need to inherit one copy of the recessive gene in order to express the recessive trait.

Question 32

Autosomal Dominant Pedigrees

Answer 32

- can't skip generations - unshaded individuals are homozygous recessive - shaded individuals are heterozygous or

Question 33

X linked recessive petigrees

Answer 33

- Can (but don't have to) skip generations - Males only need one copy of a gene to show me - If a female has it, all of her sons will have it - In order for a female to get it, her father must have it.

Question 34

How to tell whether a pedigree is sex linked:

Answer 34

- in X-linked recessive traits, males are much more commonly affected than females. - In autosomal traits, both males and females are equally likely to be affected (usually in equal proportions).