science exam review!

Question 1

what are 3 things Mendel discovered?

Answer 1

1. 2 copies of each gene are in each cell. organisms inherit one gene from mother and one from father.
2. there are dominant and recessive traits, sometimes the dominant masks the recessive
   3.disproved that traits blend (purple and white do not make light purple)

Question 2

how did he know he had purebred plants in his garden?

Answer 2

many plants were self pollinated and produced plants with the same traits

Question 3

explain an experiment he conducted with the white and purple flowers

Answer 3

-he had cross pollinated a purple flower with a white one (parental generation)
-the F1 of offspring had purple flowers (no white)
-then the F2 self pollinated and had mostly purple flowers but a little bit of white

Question 4

why is one trait lost/hidden in the F1 generation when crossing 2 different purebred plants?

Answer 4

the dominant trait masked the hidden trait in the F1 generation. all offspring were hybrid (1 dominant trait and 1 recessive trait)

Question 5

how does the hidden trait reappear in F2?

Answer 5

when the hybrid plants self pollinate, a few offspring will have 2 recessive alleles and show the recessive trait. (it can skip a generation)

Question 6

what is a allele?

Answer 6

forms of genes, each cell has 2 alleles. each gene controls which traits are expressed/can be observed

Question 7

purebred Dominant:
Purebred recessive:
Hybrid:

Answer 7

TT tall
tt short
Tt tall

Question 8

what is the ratio/percentage for traits in the F2 generation of Mendals plant exprements?

Answer 8

3 tall and 1 short (75% and 25%)
purebred dominant 1(25%)
hybrid 2: (50%)
purebred recessive: 1 (25%)

Question 9

can short pea plants be hybrid?

Answer 9

no tall alleles will mask the recessive traits. to have a short pea plants you have to have purebred recessive.

Question 10

How is this related to our study of DNA?

Answer 10

DNA is made up of genes that code for different traits (alleles)

Question 11

how is there a probability of inheritance

Answer 11

genes can be in patterns these allow us to predict which traits will be inherited.

Question 12

punnet squares

Answer 12

It allows us to know which genes will combine and which traits will be expressed and which will be masked.

Question 13

purple and white plant

Answer 13

genotypes possible: all Pp
phenotypes possible: all purple

Question 14

homozygous

Answer 14

all the same ex: TT or tt

Question 15

heterozygous

Answer 15

2 alleles of different types ex: Tt

Question 16

explain how to organisms can have the same phenotype but different genotypes?

Answer 16

ex: black puppies can look the same (phenotype) but one has Bb trait and the other has BB

Question 17

Incomplete dominance:

Answer 17

both traits are blended together ex: white and red flowers make a pink

Question 18

polygenic inheritance:

Answer 18

multiple genes

Question 19

codominance

Answer 19

both show up at the same time ex: a black and white cow make a spotted cow

Question 20

multiple alleles:

Answer 20

controlled by 3 or more genes

Question 21

What’s unusual about the sex cell?

Answer 21

they have 1/2 of the number of body cells since during reproduction they join together

Question 22

who was darwin?

Answer 22

he published a book (the origins of species)

Question 23

who was wallace?

Answer 23

he came up with the same idea after darwin had and published a book (drawinism)

Question 24

who got credit?

Answer 24

darwin because he thought of it first

Question 25

darwins theory?

Answer 25

the galapagos island had finches and tortises that looked like fossils just changed over time

Question 26

Dna and evolution?

Answer 26

we could see similar organsims had similar dna

Question 27

evolutionary tree diversity:

Answer 27

each branch represents a new species and the longer the branch the longer it took before the new species appeared

Question 28

homologous structures:

Answer 28

they are closely related on the tree

Question 29

bones are held together by what?

Answer 29

ligaments

Question 30

bones to muscles?

Answer 30

tendons

Question 31

smooth and cardiac muscles tire and involuntary?

Answer 31

smooth tires slowly cardiac never tires both are involuntary

Question 32

types of joints how do they move?

Answer 32

-pivot: rotate (neck) -hinge: move back and forth (elbow and knee) -ball and socket: move in a complete circle (hip and shoulder) -gliding: one bone moves over the other (wrist and ankle) -immoveable: joints that fused together during infancy

Question 33

the number of bones:

Answer 33

babies have 300 adults have 206 since they fuse

Question 34

functions of the skeletal system:

Answer 34

-give body shape and support -protects organs -stores minerals -makes blood cells (marrow)

Question 35

functions of the skin system:

Answer 35

-forms a protective barrier keeping good things in and bad out -produces vitamin D -gathers info about environment -maintains body temp -eliminates wastes through sweating

Question 36

top layer of skin:

Answer 36

layer of dead cells where new ones get pushes up to replace them once they fall

Question 37

how does skin keep you hot/cold

Answer 37

blood vessels close a little to keep heat in and open a little to let heat out

Question 38

difference between mechanical and chemical digestion?

Answer 38

chemical: uses saliva in the mouth Mechanical: breaks it into smaller pieces ~both break down food~

Question 39

4 chemicals of digestion:

Answer 39

-saliva: mouth -acid: Stomach -bile: produced by the liver/gallbladder -enzymes: produced by pancreas

Question 40

small and large intestine differences:

Answer 40

small: nutrients are broken down and absorbed large: absorbs extra water

Question 41

functions of the circulatory system:

Answer 41

-move blood around the body and deliver nutrients -move wastes and carbon dioxide to remove body

Question 42

how does breathing work?

Answer 42

with the diaphragm moving down to the lungs to allow lungs to inflate and moves up to push air out

Question 43

purpose of the nervous system:

Answer 43

gather info about the environment and react to it

Question 44

female sex cell:

Answer 44

-largest cell -contains x chromosome (female)

Question 45

male sex cell:

Answer 45

-smallest cell -contains either a X or Y chromosome

Question 46

where does fertilization occur?

Answer 46

through the fallopian tube during fertilization the sex cells join and becomes a zygote the gets implanted in the uterus

Question 47

eggs in ovaries:

Answer 47

females are born with all the eggs they will have in their life and they get released during a period.

Question 48

the outcome of fertilization/period

Answer 48

period-eggs release last day if fertilization doesn't occur fertilization- zygote floats down to the fallopian tube

Question 49

how long is the average period?

Answer 49

28 days although everyone is different

Question 50

4 main parts of the reproductive system:

Answer 50

ovary,fallopian tube,uterus, vagina

Question 51

how does the nervous system and the muscular system work together?

Answer 51

neurons sense environment, tell brain how to react, then muscles react to it