Name: Period: Part 2 (ANSWERS) Genetics 1) - Weebly

Name:______________________Period:____

AIMS Review Packet ¨C Part 2 (ANSWERS)

Genetics

1) What is genetics?

The science of heredity and of the mechanisms by which traits are passed from parents to offspring.

2) Who is considered to be the ¡°father¡± of genetics?

Gregor Mendel

3) What is an allele?

Variation of a gene

4) Define homozygous and heterozygous.

Homozygous: an individual that has identical alleles for a trait. (AA or aa)

Hetereozygous: an individual that has two different alleles for a trait (Aa)

5) Identify the following genotypes as homozygous recessive (HR), homozygous dominant (HD),

or heterozygous (HE):

HH

Tt

Jj

rr

Ss

MM

HH: homozygous dominant

Tt: heterozygous

Jj: heterozygous

6) Define genotype and phenotype. Give an example of each.

Genotype: the entire genetic make-up of an organism

Phenotype: the physical appearance of an organism (because of genotype)

7) What is the difference between a dominant trait and a recessive trait?

If the dominant trait is present it will be expressed in the organism¡¯s phenotype. The recessive trait only

shows in the phenotype if it is homozygous for the recessive trait.

8) Can a heterozygous individual show the phenotype of the recessive trait? Explain.

No, Only if the organism is homozygous recessive. Otherwise the dominant trait will mask the recessive.

9) Explain the uses of a karyotype.

Used to diagnose CHROMOSOMAL ABNORMAILTIES (EXAMPLE: Down syndrome)

Also can find out the sex of the person.

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10) If Sally has dimples and is heterozygous, what can you conclude about dimples?

Dimples is the dominant trait.

11) Everyone in Squidward¡¯s family has blue skin, which is the dominant trait. Squidward is heterozygous for his blue

skin. His wife has green skin.

B

b

a. Create a Punnett square to show the possible genotypes of their children.

b. What are the possible genotypes? _______Bb , bb______

c. What are the possible phenotypes? ____green skin, blue skin__

b

Bb

bb

d. What are the chances of a child with blue skin? ____50%____

e. What are the chances of a child with green skin? ______50%______

f.

Phenotypic ratio: ____1:1 or 2:2___________

b

Bb

bb

g. Genotypic ratio: _____0:1:1 or 0:2:2___(¡°0¡± for BB genotype)___

12) What is Incomplete dominance? Give an example

When both alleles are present there is a blending of the phenotype.

Example: rr=White flower : RR=Red flowers : Rr=pink flowers

13) What is Co dominance? Give an example.

When both traits are expressed at the same time. Dog with black and white spots or Barred Rock Chicken

14) Sex linked genes tend to be carried on what sex chromosome?

X chromosome

15) What sex chromosomes does a male carry? Female?

Males: XY Females: XX

16) If S= striped and s= solid, what are the phenotypes for each of the following:

a) Ss, Striped

b) SS, Striped

c) ss, Solid

17) If brown hair is dominant (B) to blonde hair (b), and two parents have a brown hair child, what are the possible

genotypes of each parent? BB or Bb

t

t

18) If the gene for tall plants was incompletely dominant over the gene for short plants,

what are the possible genotypes and phenotypes of the offspring when a tall plant is

crossed with a short plant? Complete the cross.

T

Tt

Tt

T = tall t= short

TT = tall height

Tt = medium height

tt = short height

For TT x tt the offspring will all be medium height.

T

Tt

Tt

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19) In horses the coat color is controlled by co-dominant alleles. The alleles for a red coat or white coat are both

expressed in a heterozygote. Horses that have a both a red and white coat are said to have a roan coat (both red

and white hairs). Horses that have neither of the dominant alleles have a blonde coat. Cross two individuals with

roan coats. Calculate the phenotypic (PR) and genotypic ratios (GR).

R

r

Rr x Rr

RR : Rr : rr

PR 1 : 2 : 1

R

RR

Rr

r

Rr

rr

GR 1 : 2 : 1

X

20) The gene for baldness is carried on the x-chromosome. What are the chances that a

bald man and a carrier (heterozygous) woman would have a bald boy? A bald girl?

Show the cross.

c

Bald Girl = 25% Chance

X

c

Bald Man Genotype = X Y

c

Carrier Woman Genotype = XX

c

c

X

c c

X X

X X

XY

X Y

Bald Boy = 25% Chance

Y

c

21) Draw a pedigree and find the genotypes for the following situation tracking the instance of the recessive trait blonde

hair: A blonde man marries a brown haired woman. They have two daughters who both have brown hair and a son

with blonde hair. Their son has a son of his own with brown hair.

Male =

Female =

?Brown Hair?

?Blond Hair?

Photosynthesis/Cellular Respiration

22) What is an autotroph? Give examples

Organism that creates its own energy ¡°auto¡±matically ; ex) plants

23) What is a heterotroph? Give examples

Organism that needs to eat to gain energy ; ex) animals

24) How are autotrophs and heterotroph linked?

Both important part of the food chains/webs; both rely on each other for reactants and products of photo/CR

25) Why is chlorophyll green?

Chlorophyll absorbs all wavelengths of light EXCEPT green

26) What is photosynthesis?

A process in which plants capture the suns energy to convert to ¡°food¡±

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27) What is the equation for photosynthesis? Label the reactants and products.

CO2 + H2O + Energy

??C6H12O6 + O2

Products =C6H12O6 + O2 (glucose and oxygen)

Reactants = CO2 + H2O + Energy (carbon dioxide, water, energy from the sun)

28) Where does photosynthesis occur?

Within Chloroplasts

29) Where does the light reaction occur? What goes into this reaction? What comes out?

Thylakoid membrane of chloroplasts; water and carbon dioxide; oxygen and ATP / NADPH

30) Where does the dark reaction (Calvin cycle) occur? What goes into this reaction? What comes out?

Stroma of the chloroplasts ; Carbon dioxide, glucose

31) Which pigment is directly involved with photosynthesis? (The primary pigment)

Chlorophyll

32) Why are carotenoids and chlorophyll b (alternatives to chlorophyll a) important to photosynthesis?

They absorb different wavelengths of light than chlorophyll ¡°a¡± to maximize sunlight energy intake. Like, for

example, when the sun rises lower in the sky in the fall and winter.

33) What three factors affect the rate of photosynthesis?

Temperature, carbon dioxide levels, amount of energy from sun

34) Does photosynthesis occur in the roots, leaves or stems?

Leaves!

35) Why does photosynthesis not occur in the other two places?

Lack of chlorophyll

36) What is an aerobic pathway? Give an example.

Pathway taken by cells to create energy if oxygen is present

37) When does aerobic respiration occur?

All the time ; when oxygen is available

38) What is an anaerobic pathway? Give 2 examples.

Pathway taken by cells when oxygen is absent ; lactic acid fermentation and alcoholic fermentation

39) What type of cellular respiration does yeast undergo?

Fermentation

40) What is cellular respiration?

A process in which mitochondria use oxygen and glucose to make ATP (energy) for the cells.

41) Which is the equation for cellular respiration? Label the reactants and products.

C6H12O6 + O2 ??CO2 + H2O + Energy

Products: CO2 + H2O + Energy (carbon dioxide, water, ATP)

Reactants: C6H12O6 + O2 (Glucose and oxygen)

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Name:______________________Period:____

42) Where does aerobic respiration occur in a eukaryotic cell? In a prokaryotic cell?

Eukaryotic cell = mitochondria

Prokaryotic cell = cytoplasm (since prokaryotes don¡¯t have mitochondria)

43) Why do cells need energy?

To perform most cellular functions (protein

synthesis; active transport, etc)

44) How much ATP can be produced from a complete

breakdown on one glucose molecule? Include all the

steps.

38 ATP

45) How does the amount of energy produced in cellular

respiration compare with energy produced during

fermentation?

Fermentation simply keeps glycolysis going, so

therefore making 2 ATP every cycle.

46) Glucose is broken down during glycolysis to form

what? What else is formed?

Pyruvic acid ; NADH ??will most likely NOT be

on AIMS

47) Why are photosynthesis and cellular respiration reciprocal parts of a cycle? (How are they linked to each other?)

The products of PHOTO become the reactants in CR and visa versa

48) Describe what is happening in graph 1. Explain why?

As light intensity increases, rate of photosynthesis increase ; the more photon exposed to, the more ATP and

NADPH can be made ? therefore leading to more glucose in the dark reactions

49) Describe what is happening in graph 2. Explain why?

As temperature increases, so does the rate of photosynthesis¡­. To a point! After about 25 o Celsius,

temperature has a negative effect on the rate of photosynthesis.

Ecology

50) List the levels of organization for populations from smallest to largest for Ecology. Understand the differences.

Organism (one individual) ??Population (more than one of the same species) ???

Community (one species population and all the other living populations in the area) ???

Ecosystem (All the living and non-living things that interact) ??Biosphere (where life is found on the earth)

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