Chapter 7- genetics

Question 1

What is genetics?

Answer 1

The scientific study of heredity

Question 2

What is heredity?

Answer 2

The passing on of characteristics from parents to offspring (these characteristics are called traits)

Question 3

What traits did Mendel study?

Answer 3

Height, seed color, and flower color

Question 4

What type of plant did Mendel use to study heredity?

Answer 4

True breeding pea plants

Question 5

What does the pistil produce?

Answer 5

Female sex cells (or eggs)

Question 6

What does the stamen produce?

Answer 6

Pollen which contains male sex cells (or sperm)

Question 7

When does a new organism begin to form?

Answer 7

When egg and sperm cells join in the process of fertilization

Question 8

What needs to happen in order for fertilization to occur?

Answer 8

Pollen must reach the pistil of a pea flower (this is called pollination)

Question 9

What is self pollination?

Answer 9

Pollen from a flower lands on the pistil of the same flower

Question 10

If a true breeding plant has purple flowers then what will it produce?

Answer 10

It will only produce plants with purple flowers

Question 11

If a true breeding plant (purple) was allowed to self pollinate then what would happen?

Answer 11

They would only produce offspring identical to themselves

Question 12

How many traits of pea plants did Mendel study?

Answer 12

7

Question 13

How many traits at a time did Mendel study?

Answer 13

1

Question 14

How did Mendel see how height was passed from parent to offspring?

Answer 14

He took pollen from a true breeding tall pea plant and cross pollinated a true breeding short pea plant?

Question 15

What did Mendel notice after seeing how heights was passed from parent to offspring?

Answer 15

He noticed that a trait from the parent pea plant did not always show up in the offspring (1st generation)

Question 16

What method did Mendel use to better control his experiments?

Answer 16

Cross pollination

Question 17

What part of the flower contains pollen?

Answer 17

Anthers

Question 18

Why did Mendel remove the anthers in his experiments?

Answer 18

So that the flower could not self pollinate

Question 19

What happened when Mendel crossed true breeding (purple-flowered) plants with true breeding (white-flowered) plants?

Answer 19

The 1st generation produced all purple flowered plants (homozygous dominant and recessive cross)

Question 20

What happened when the purple flowered plants of the offspring self pollinated ?

Answer 20

White flowers reappeared (heterozygous cross)

Question 21

Hybrid

Answer 21

Offspring of parents that have different forms of a trait

Question 22

What did Mendel conclude?

Answer 22

• sets of genetic info. must control the inheritance of traits in peas
• the factors that control each trait exists in pairs
• the female and male parent both contribute one factor
• one factor in a pair can mask, or hide, the other factor

Question 23

What are the factors that determine traits called?

Answer 23

Genes

Question 24

Alleles

Answer 24

Different forms of genes

Question 25

What are an organisms’ traits controlled by?

Answer 25

The alleles it inherits from its parents

Question 26

What are the two options for an allele?

Answer 26

Dominant, recessive

Question 27

Dominant allele

Answer 27

An allele whose trait always shows when the allele is present

Question 28

Recessive allele

Answer 28

Hidden whenever the dominant allele is present (can only show with two recessive alleles)

Question 29

What do geneticists use to represent alleles?

Answer 29

Letters (dominant= capital, recessive= lowercase)

Question 30

Law of segregation

Answer 30

- every organism has two alleles of each gene | - when gametes are produced the alleles separate

Question 31

Phenotype

Answer 31

The way an organism looks and behaves (you can physically see it)

Question 32

Genotype

Answer 32

The allele combination of an organism

Question 33

Law of Independent Asoortment

Answer 33

-genes for different traits are inherited independently of each other

Question 34

Probability

Answer 34

A number that describes how likely something is to happen

Question 35

What law describes what is likely to occur (not what will occur)?

Answer 35

Law of probability

Question 36

Punnett square

Answer 36

Chart that shows all the possible ways an allele can combine in a genetic cross

Question 37

What is the combination of alleles that parents can pass on to an offspring based on?

Answer 37

Probability

Question 38

Monohybrid

Answer 38

Cross of one trait

Question 39

How many chromosome do sex cells have?

Answer 39

Half as many chromosomes as the body cells have

Question 40

Diploid

Answer 40

A complete set of chromosomes

Question 41

Haploid

Answer 41

A half set of chromosomes

Question 42

Meiosis

Answer 42

Process by which the number of chromosomes is reduced by half as sex cells form

Question 43

Result of meiosis

Answer 43

4 genetically different haploid cells

Question 44

Where does meiosis occur in?

Answer 44

A diploid cell

Question 45

How many cell divisions does meiosis go through?

Answer 45

2

Question 46

How many interphases are there in meiosis?

Answer 46

1

Question 47

Interphase

Answer 47

Chromosomes double and thicken

Question 48

Prophase 1

Answer 48

Nuclear membrane disappears (spindle fibers attach)

Question 49

Metaphase 1

Answer 49

Homologous pairs line up in the middle

Question 50

Anaphase 1

Answer 50

Homologous pairs separate (not the chromosomes)

Question 51

Telophase 1/ cytokinesis 1

Answer 51

- nuclear membrane reforms | - cell splits

Question 52

Prophase 2

Answer 52

Nuclear membrane disappears (spindle fibers attach)

Question 53

Metaphase 2

Answer 53

Chromosomes line up at center

Question 54

Anaphase 2

Answer 54

Chromosomes split

Question 55

Telophase 2/ cytokinesis 2

Answer 55

- nuclear membrane reforms | - cells split

Question 56

Why are the 4 cells genetically different?

Answer 56

Cross-over and recombination

Question 57

What happens in crossover?

Answer 57

Homologous chromosomes pair up (tangle)

Question 58

What happens in recombination?

Answer 58

Parts of the chromosomes switch (trading sections of DNA)