SCIENCE REVIEWER (3)

LESSON 2.2-3.3

first examined the genes. He called this "elementen".

Gregor mendel

Were based on the behaviour of chromosomes during meiosis and fertilization

Medilian Principles

Carriers of genes: the unit determiners of heredity character

Chromosomes

derived from the Greek words. chroma meaning =

color

soma

body

shaped like a ball, contained by chromosome and the genetic material or DNA coiled around it.

Histones

carries the a long coiled structure that carries the genetic instructions on how living things would grow and develop

DNA (deoxyribonucleic acid)

the portion of DNA in specific patterns that are responsible for the physical and heritable characteristics of organisms.

Genes

the nucleoid is a region of cytoplasm where the chromosomal DNA is located

Prokaryote

the extra circular DNA

Plasmid

chromosomes are found in the nucleus of the cell.

Eukaryotes

Chromosomes are tightly packed in the nucleus

Chromatins

double-stranded chromosomes that are highly coiled x-shaped structure.

Sister Chromatids

the pinched area in the pair of chromatids.

Centromere

The short arm is called the

P arm (Petitè)

The longer arm is called the

Q arm (next letter after p in the alphabet)

all living things have a characteristic number of chromosomes in their body cells. (somatic cells)

HOMOLOGOUS Chromosome

Humans have __ chromosomes

46 (23 pairs)

Humans have ______ cells

Diploid cells

Haploid number (N)

23

Diploid number (2N)

46

egg + sperm cell =

gametes

Fertilized egg

Zygote

any increase I decrease in number of chromosomes. that can lead to death. of an organism.

Mutation (inviability)

increasing the number of Chromosomes

Polyploidy

the heritable condition of possessing more than two complete sets of chromosomes

Polyploidy

these are common among plants, as well as among the groups of fish and amphibians

Polyploidy

Each member of the pair of homologous chromosomes does. not originate from the same origin:

one maternal chromosome

• one paternal chromosome

and only pair up during meiosis.

an actual picture of the chromosomes from one cell that has been studied and analyzed by cytogenetic technologists.

Karyotype

the study of chromosomes.

Cytogenetics

46 chromosomes are arranged in __ pairs

23

are the 22 pairs

Homologous autosomes

The last Pair is called

sex chromosomes or genosomes.

Female

XX chromosomes

Male

XY chromosomes

the "Father of Heredity!

Gregor Johann Mendel

the cross between organisms with two different phenotypes where neither of trait of these parents is expressed.

Principle of Incomplete Dominance

the organisms appearance (physical).

Phenotypes

the combination of alleles it's parents (genes). an organisms inherits from

Genotype

Capital Letter

Dominant allele

Lowercase letter

Recessive allele

The traits carried by the genes located on the Sex chromosomes (xx or XY).

Sex linked traits

If the gene is located on the X chromosome, it is called an

X linked gene

If the gene Y-linked is located on the y chromosome, it is called an

Y-linked gene

Xny

Expressed

xYn

Not Expressed

The ___ molecule is a long, coiled, structure that carries the genetic instructions on how living things would grow and develop

DNA

All living things have a characteristic number of chromosomes in their body cells

Somatic cells

Thread-like structures composed of proteins called Histones and DNA molecules. They are the carriers of genes, the unit determiners of heredity characteristics

Chromosomes

Chromosomes always occur in

Pairs

Chromosomes with the same size, shape, and banding patterns carry the same genes are called

Homologous chromosomes

In _____ alleles, one alleles is dominant and the other is Recessive

Heterozygous alleles

Is a genetic disorder characterized by progressive muscle degeneration that leads to muscle weakness. This is caused by the mutation of the gene in the X chromosome that keeps the muscle cells intact.

Duchenne muscular dystrophy (DMD)

red-green color blindness

X-linked(trait) recessive disorder

Is a red blood cell disorder wherein the red blood cells are shaped like crescent moons or sickles. The cells cannot carry enough oxygen.

Sickle cell anemia

Hemophilia

An X-linked recessive disorder in which blood fails to clot properly, leading to excessive bleeding if injured.

The genes for a particular trait are located in specific ____ in the chromosomes.

Loci

Traits controlled by multiple alleles

blood type(human blood groups)

Scientists who study the genes of all living things

Geneticists

The physical appearance (phenotype) is determined by a pair of _____

Genes

Cases where the heterozygous characteristics are both fully expressed

Codominance

A ____ coat color is one in which the coat color is a mixture of red and white coat color

Roan coat color

_____ trait refers to a trait whose physical appearance is a result of the cumulative expression of multiple genes (skin color, eye color, hair color, height, and weight)

Polygenic traits

The law of incomplete dominance states that in heterozygous alleles, one allele is not completely dominant over the other allele, resulting in ________

Blending of characteristics.

_______ alleles refer to traits controlled by 3 or more alleles.

Multiple alleles

Traits that are found and controlled by genes in the sex chromosomes

Sex-linked traits

The physicist who introduced the very popular atomic theory in chemistry, was also the first scientist to study color blindness

John Dalton

International Color Blindness Awareness Day

September 6 (Dalton's birthday)

contain the haploid number of chromosomes.

Gametes or sex cells

is the union of the egg and sperm. The union results in the formation of a diploid zygote that grows by mitosis into a multicellular organism.

Fertilization

are composed of coiled DNA molecules located in the nucleus of eukaryotic cells.

Chromosomes

the variety of life on Earthat any given site or ecosystem is known as ______

Biodiversity

THREE LEVELS OF BIODIVERSITY:

1. SPECIES DIVERSITY

2. GENETIC DIVERSITY

3. ECOSYSTEM DIVERSITY

​

planet Earth houses about

10-30 million species of living things.

species that have been named and classified

1.8 million

The richest ecosystem in the world (50-80% of species live here)

Tropical rain forest

The term "biodiversity" was coined by ____ in 1985 and was introduced to the science communities by Thomas E. Lovejoy.

Raymond F. Dasmann

Biodiversity exists on three levels:

species, genetic, and ecosystem diversity.

_____ diversity pertains to the total number of species that exist within a region, as well as the number of individuals composing each species and how they interact with each other and the physical environment.

Species diversity

A ______ is a group of organisms possessing a unique set of characteristics.

Species

______ diversity pertains to the variations in genes (genetic makeup or genotype) between distinct species.

Genetic diversity

exists as a result of the variations in the sequence of the four base pairs that compose the DNA nucleotide, the building block of nucleic acids.

Genetic diversity

In a DNA molecule, the bases that pair are:

adenine, guanine, cytosine, and thymine.

_____ diversity pertains to the variety of ecosystems: forests (temperate and tropical), savannas, grasslands, deserts, wetlands, ponds, and the various types of habitats found within each type.

Ecosystem diversity

is one of the pressing issues of our time. This is actually a worldwide concern.

Biodiversity loss

THREE TYPES OF BIODIVERSITY LOSS:

1. EXTINCTION OF SPECIES

2. LOSS OF SPECIFIC HABITATS

3. LOSS OF GENETIC VARIATIONS WITHIN A SPECIES

if there is a continuous decrease or extinction of species, loss of specific habitat, and loss in the genetic variations within a species.

Biodiversity loss

is the number one cause of biodiversity loss. means the last individual belonging to a particular species is gone forever.

Extinction of species

All species have specific basic needs. A habitat is a place where organisms live. It provides the necessary elements of life like food, shelter, and the like.

Loss of specific habitats

plays an important role in the survival and ability of the species to adapt to changing environments.

Loss of genetic variations within a species

The higher the genetic variation is among the species, the ____ of survival of the species.

greater