Science Ch. 2-5

Front 1

physical characteristics

Back 1

traits

Front 2

the passing of traits from parents to offspring

Back 2

heredity

Front 3

a plant or animal that always produces offspring with the same form of a trait as the parent

Back 3

purebred

Front 4

factors that control traits

Back 4

genes

Front 5

different forms of a genes

Back 5

alleles

Front 6

Individual ________ control the inheritance of traits

Back 6

alleles

Front 7

A __________ allele is one in which the trait always shows up in the organism when the allele is present

Back 7

dominant

Front 8

A __________ allele is masked or covered up whenever the dominant allele is present

Back 8

recessive

Front 9

True or false: A trait controlled by a recessive allele will only show up if the organism does not have the the dominant allele

Back 9

True

Front 10

an organism that has two different alleles for a trait;

Back 10

hybrid

Front 11

the likelihood that a particular event will occur

Back 11

probability

Front 12

Mendel was the first scientist to realize that the principles of probability can be used to predict

Back 12

the results of genetic crosses

Front 13

a chart that shows all the possible combinations of alleles that can result from a genetic cross

Back 13

Punnett square

Front 14

Geneticists use Punnett squares to: 1)show all possible __________ and 2) to determine the probability of ____________

Back 14

1) outcomes of a genetic cross
2) a particular outcome

Front 15

an organism's genetic makeup or allele combinations

Back 15

genotype

Front 16

a __________ organism has two identical alleles for a trait

Back 16

homozygous

Front 17

A ___________ organism has two different alleles for a trait

Back 17

heterozygous

Front 18

an organism's physical appearance, or its visible traits

Back 18

phenotype

Front 19

an inheritance pattern in which the alleles are neither dominant nor recessive

Back 19

codominance

Front 20

the male sex cell

Back 20

sperm

Front 21

the female sex cell

Back 21

egg

Front 22

The chromosome theory of inheritance states that _________ are carried from parents to their offspring on chromosomes

Back 22

genes

Front 23

the process by which the number of chromosonmes is reduced by half to form sex cells

Back 23

meiosis

Front 24

During meiosis, the _________ pairs separate and are distributed to two different ______.

Back 24

chromosome, cells

Front 25

During meiosis, the resulting sex cells have only half as many _________ as the other cells in the organism

Back 25

chromosomes

Front 26

The main function of genes is to control the production of _________ in the organism's cells

Back 26

proteins

Front 27

The order of the _______ bases along a gene forms a genetic code that specifies what type of _______ will be produced.

Back 27

nitrogen, protein

Front 28

During ______ ________, the cell uses information from a gene on a chromosome to produce a specific protein.

Back 28

protein synthesis

Front 29

____________ RNA copies the coded message from the DNA in nucleus and carries the message into the cytoplasm

Back 29

messenger

Front 30

_________ RNA carries amino acids and adds them to the growing protein

Back 30

transfer

Front 31

a change in gene or chromosome

Back 31

mutation

Front 32

True or false: All changes brought about by mutations are harmful to an organism.

Back 32

False. Some are harmful, some are helpful, and some are neither.

Front 33

three or more forms of a gene that code for a single trait

Back 33

multiple alleles

Front 34

Some human traits show a large number of phenotypes because the traits are controlled by a large number of _______ that act together as a group to produce a single trait.

Back 34

genes

Front 35

Give an example of how the environment can alter the effect of a person's genes.

Back 35

A poor diet can keep a person from growing to his maximum potential height.

Front 36

Genes on the X and Y chromosomes are often called _____-________ ________.

Back 36

sex-linked genes

Front 37

a tool that geneticists use to trace the inheritance of traits in humans

Back 37

pedigree

Front 38

Any allele on the ___ chromosome (even a recessive allele) will produce the trait in a male who inherits it.

Back 38

X

Front 39

an abnormal condition that a person inherits through genes or chromosomes

Back 39

genetic disorder

Front 40

Genetic disorders are caused by _________, or changes in a person's DNA.

Back 40

mutations

Front 41

Name two tools that doctors use to detect genetic disorders.

Back 41

amniocentesis, karyotypes

Front 42

a technique by which a small amount of the amniotic fluid is removed and analyzed to determine whether the baby will have a genetic disorder

Back 42

amniocentesis

Front 43

a picture of all the chromosomes in a cell arranged in pairs

Back 43

karyotype

Front 44

the process of selecting a few organisms with desired traits to serve as parents of the next generation

Back 44

selective breeding

Front 45

a selective breeding method that involves crossing two individuals that have identical or similar sets of alleles

Back 45

inbreeding

Front 46

a selective breeding method in which two genetically different individuals are crossed

Back 46

hybridization

Front 47

an organism that is genetically identical to the organism form which it was produced

Back 47

clone

Front 48

How can a clone of a plant be produced?

Back 48

through taking a cutting from the plant and growing it into a new plant

Front 49

the transfer of a gene from the DNA of one organism into another organisim in order to produce an organism with desired traits

Back 49

genetic engineering

Front 50

the insertion of working copies of a gene into the cells of a person with a genetic disorder in an attempt to correct the disorder

Back 50

gene therapy

Front 51

DNA is like fingerprints because no two people have the same DNA, except for _________ ______.

Back 51

identical twins

Front 52

What is the main goal of the Human Genome Project?

Back 52

to identify the DNA sequence of every gene in the human genome

Front 53

Darwin thought that species gradually changed over many _____________ as they became better adapted to new ___________.

Back 53

generations, conditions

Front 54

Darwin's observations led him to propose that evolution occurs through ________ ___________.

Back 54

natural selection

Front 55

a group of similar organisms whose members can mate with one another and produce fertile offspring

Back 55

species

Front 56

the gradual change in a species over time

Back 56

evolution

Front 57

the process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species

Back 57

natural selection

Front 58

Natural selection occurs due to ___________, ___________ and ____________.

Back 58

overproduction, competition and variations

Front 59

a characteristic that helps an organism survive in its environment or reproduce

Back 59

adaptation

Front 60

Only traits controlled by _______ can change over time as a result of natural selection.

Back 60

genes

Front 61

According to the theory of evolution, what can happen if a group of individuals remains separated from the rest of its species long enought to evolve different traits?

Back 61

a new species can form

Front 62

a well-tested concept that explains a wide range of observations

Back 62

scientific theory

Front 63

any difference between individuals of the same species

Back 63

variation

Front 64

the preserved remains or traces of an organism that lived in the past

Back 64

fossil

Front 65

a type of rock that forms when particles of other rocks or the remains of plants and animals are pressed and cemented together

Back 65

sedimentary rock

Front 66

Most fossils form when organisms die and sediments _____ them. The sediments __________, preserving parts of the organism

Back 66

bury, harden

Front 67

a fossil in which minerals replace all or part of an organism

Back 67

petrified fossil

Front 68

a fossil formed when an organism buried in sediment dissolves, leaving a hollow area

Back 68

mold

Front 69

a fossil that is a copy of an organism's shape, formed when minerals seep into a mold

Back 69

cast

Front 70

a technique used to determine which of two fossils is older

Back 70

relative dating

Front 71

a technique used to determine the actual age of a fossils

Back 71

absolute dating

Front 72

___________ help scientists undestand how extinct organisms looked and evolved.

Back 72

Fossils

Front 73

The _________ ______ _______ shows when during the Earth's history major groups of organisms evolved.

Back 73

Geologic Time Scale

Front 74

____________ has occurred gradually at some times and fairly rapidly at others.

Back 74

Evolution

Front 75

an unstable particle that breaks down into a different element

Back 75

radioactive element

Front 76

the time it takes for half of the atoms of a radioactive element to decay

Back 76

half-life

Front 77

The millions of fossils that scientists have collected is referred to as the ________ ________.

Back 77

fossil record

Front 78

An _________ species does not have any living members

Back 78

extinct

Front 79

the theory that evolution occurs slowly but steadily

Back 79

gradualism

Front 80

the theory that species evolve during short periods of rapid change

Back 80

punctuated equlibria

Front 81

By comparing modern day organisms, scientist can infer how closely related they are in an ______________ sense.

Back 81

evolutionary

Front 82

body parts that are stucturally similar in related species; these provide evidence that the structures were inherited from a common ancestor

Back 82

homologous structures

Front 83

three things scientists consider to determine how closely species are related and whether they share a common ancestor

Back 83

similarities in early developmental stages, body structures and DNA sequences

Front 84

a diagram that shows how scientists think different groups of organisms are related

Back 84

branching tree