genetics

Question 1

what is DNA shaped like

Answer 1

a twisted ladder

Question 2

What are the nitrogen bases?

Answer 2

1. adenine (A)
2. tymine (T)
3. cytosine (C)
4. guanine (G)

Question 3

RNA is made up of what?

Answer 3

• made up of sugar ribose

Question 4

What strand is RNA?

Answer 4

single-stranded

Question 5

In RNA what is thymine replaced by?

Answer 5

Thymine is replaced by uracil (U)

Question 6

the combination of alleles in an organism is called its….

Answer 6

Genotype

Question 7

what is a Genotype

Answer 7

full set of genes contained in an organism’s DNA, and the alleles that the organism has for those genes

Question 8

An individual’s genotype is made of…..

Answer 8

the alleles inherited from both parents

Question 9

An individual’s phenotype depends on….

Answer 9

both its genotype and its environment

Question 10

Phenotype can be changed by….

Answer 10

the environment

Question 11

Genotype affects phenotype by providing…

Answer 11

the instructions for making proteins

Question 12

Phenotype is an…

Answer 12

organism’s visible characteristics

Question 13

Phenotype is the set of characteristics that results from both…..

Answer 13

an organism’s genotype and its environment

Question 14

The cells that make up the body are called:

Answer 14

somatic cells

Question 15

somatic cells divide by a process called:

Answer 15

mitosis

Question 16

explain the process of mitosis

Answer 16

• Mitosis makes 2 daughter cells (identical to parent cell)

-daughter cells have same alleles as the parent cell = the genotype of an individual does not change as it grows

Question 17

what passes on genes from parents to children

Answer 17

germ cells

Question 18

characteristics of germ cells

Answer 18

• two sets of chromosomes

-make other cells called gametes (with 4 chromosomes each)

-each germ cell can make 4 gamete cells through meiosis

Question 19

what is a cell with two sets of chromosomes referred as?

Answer 19

diploid cells

Question 20

female vs male gametes

Answer 20

• Female gametes are called egg cells
• Male gametes are called sperm cells

Question 21

define gametes

Answer 21

gametes are sex cells that are only used for reproduction

Question 22

cell with one set of chromosomes

Answer 22

haploid cells

Question 23

2 examples of haploid cells:

Answer 23

1. sperm cell
2. egg cell

Question 24

what must occur before meiosis?

Answer 24

• the germ cell must prepare to divide
• must double its DNA and make more organelles and cytoplasm (interphase)

Question 25

Sometimes the DNA is not copied correctly. This creates a new allele. When this happens, it is called….

Answer 25

A mutation

Question 26

Sister chromatids vs homologous chromosomes

Answer 26

Sister chromatids = identical (same genes, same alleles)

Homologous chromosomes = same genes, but may have different alleles

Question 27

How many times must the germ cell split in half to create four gametes?

Answer 27

Each division doubles the number of cells, so the germ cell must divide twice to make four gametes.

Question 28

Meiosis I vs Meiosis II

Answer 28

• There is no interphase before meiosis II, so DNA is not replicated
• Crossing over does not happen in prophase II.

Question 29

Fertilization requires 2 what?

Answer 29

• two haploid cell
• fertilization requires a haploid sperm and a haploid egg.

Question 30

does crossing over occur in mitosis

Answer 30

no