SCIENCE 2ND SEMESTER

• 1. Cells are the basic unit of life.
• 2. All cells arise from existing cells.
• 3. All organisms are made of one or more cells.

It has a nucleus and membrane-bound organelles. It is bigger than prokaryote and it forms both multicellular and unicellular organisms.

It does not have a nucleus or membrane-bound organelles, but it has a cell wall. DNA is found in the cytoplasm and it is called a nucleoid. It is smaller than eukaryote and it forms only unicellular organisms.

Any of a number of organized or specialized structures within a living cell.

It controls the cell activities and it is the location of genetic material (DNA).

It is the location of the ribosome production.

A series of interconnected small tubes that collect proteins for transport through the cell. It is covered with ribosomes.

The location of protein synthesis (being made).

It modifies and transports macromolecules.

It provides energy to the cell. It also breaks down sugars to release energy, or does cellular respiration.

It uses energy from the sun to synthesize sugar, or it does photosynthesis.

It controls the movement of materials into and out of the cell. It is the barrier between the cell and the environment.

It is the result of cells producing new cells through cell division. As this occurs, cells differentiate to develop into specialized cells with different functions.

When the cells surrounding an injury are stimulated to divide repeatedly to form what is missing. This is called regeneration.

The production of offspring by a sexual or asexual process.

The sequence of phases in the life cycle of a cell. There are two parts: interphase and cell division, which includes mitosis and cytokinesis.

The part of the cell cycle that occurs between divisions. It is the 90% of total time in cell cycle. It is the growth and preparation phase.

Growth and development of the cell. Normal cell metabolism(how fast the body uses energy).

The chromosomes (contain DNA) replicate, or make copies of themselves.

Cell synthesizes organelles and other materials. Centrioles replicate to form two pairs.

Mitosis and cytokinesis

The process in which a nucleus divides to form two new nuclei. During this process, the DNA duplicates and then divides into two identical sets. One-celled organisms reproduce by this process.

The process in which the cytoplasm divides into two parts. Each of the two new parts contains a newly formed nucleus with one set of genetic material as well as half the number of the original, or parent cell.

Chromosomes in nucleus condense. In the cytoplasm, a bridge of proteins assemble into microtubules, forming a fibrous structure called the mitotic spindle. In late prophase the the mitotic spindle stretches out between opposite poles of the cells. The nuclear envelope and nucleolus break into fragments and disappear. The centromeres of chromosomes attach to spindle fibers, which move them toward the center of the cell.

The chromosomes are pulled to the center of the cell which is called metaphase late. Then each chromosome is lined up at an equal distance from the ends of the cell.

In this phase centromeres divide and spindle fibers pull chromatids apart toward opposite poles of cell. Two identical sets of daughter chromosomes or DNA is created.

It is the last phase, two daughter nuclei are formed. It is the reverse of prophase because nuclear envelopes form around each set of chromosomes. Chromosomes uncoil to form loose mass of chromatin and the mitotic spindle disappears.

The hereditary, or genetic material of the cell that has information on how to make cell parts and instructions for RNA to use on how to make proteins. It is found in the form of a double helix. It also has information that controlscellular activities. This controls how an organism is made up and how it works as a whole.

The term used for the form of nuclear DNA that is a mass of thin, twisted thread that are wound around proteins called histones. DNA is found in this form throughout most of interphase, when the cell is not dividing. It makes up a chromosome.

It is DNA that is condensed into short, thick rod-like structures. There are most noticeable when the cell is about to divide or is in the process of dividing. Each replicated chromosome consists of two sister chromatids.

A half of a double chromosome.

The point where sister chromatids are joined together.

Microtubules which form and stretch across the cell to act as guides and separate chromosomes.

Organizes mitotic spindle and is involved in completion of cytokinesis.

Is the uncontrolled division of particular cells.

It stops mitosis which prevents the cancer cells from dividing and therefore stops the tumor of cancer from growing.

• A compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA
• components.

One of the components of a nucleotide, contains 5 carbon atoms.

One of the components of a nucleotide.

One of the components of a nucleotide, four nitrogenous bases: Adenine. Thymine, Cytosine, and Guanine

One of the four acid compounds, always together with Thymine.

One of the four acid compounds, always together with Guanine.

One of the four acid compounds, always together with Cyotosine.

One of the four acid compounds, always together with Adenine.

Pairs of DNA that fit together.

The shape of a DNA. Double because it has got two strands and helix because the shape that it is coiled so it is easier to repicate.

The action of copying exactly the same

The production of offspring by combining genetic material from two parent organisms. Offspring are genetically different from parents.

The production of offspring by a single parent without combining genes(DNA) from another individual. Offspring are genetically identical to parent.

Body cells that have a charecteristic number of chromosomes. Humans have 46 chromosomes (23 pairs)

Sex cells, that contain only 23 chromosomes, are combined to produce offspring.

Female gamete.

Male gamete.

The fusion of the nuclei of male and female gametes.

The single cell formed during fertilization. male gamete + female gamete=zygote (n+n=2n)

A cell with only one complete set of chromosomes (1n).

Any cell that contains two complete sets of chromosomes. (2n)

All human somatic cells contain 46 chromosomes, arranged in 23 pairs. Each of the 23 pairs is called...

Homologous pair of double chromosomes (4 chromatids)

The exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring.

• Prophase I
• Metaphase I
• Anaphase I
• Telophase I
• Cytokinesis I

• Prophase II
• Metaphase II
• Anaphase II
• TelophaseII
• Cytokinesis II

• I: The replicated pairs of homologous chromosomes condense and attach to each other ensuring each pair will separate during meiosis, tetrads, genes, and crossing over.
• II: The nuclear membrane disappears, chromosomes condense, spindle fibers reform and attach to centromeres of double chromosomes, and centrioles move to poles of the cells.

• I: The spindle fibers arrange the homologous chromosomes in the middle of the cell-metaphase plate and each chromosome is lined up at an equal distance from the ends of the cell.
• II: Double chromosomes are arranged along the center of the cell by the spindle fibers.

• I: Spindle fibers separate the homologous chromosomes apart toward opposite poles of cell and chromatids of each chromosome DO NOT separate.
• II: Sister chromatids are pulled apart by spindle fibers and single chromosomes move to opposite poles of the cell.

• I: The result of Meiosis I: It is separated into 2 cells
• II: Nuclear envelopes reform, chromosomes de-condense, and cytoplasm divides producing 4 haploid cells with different DNA combinations.

It determines whether offspring are male or female.

It is a non-sex chromosome.

A photograph of all of an organism's chromosomes.

A unit of hereditary (genetic) material or DNA that controls a particular trait of a particular organism.

The different versions of the same gene.

When an organism has two of the same allele.

When an organism has two different alleles.

When only one of the two different alleles in a heterozygous individual affects the trait. This allels hides the other allele and it is represented by the capital letter.

The allele that is hidden by a dominant allele. It is represented by the lower case letter.

The genetic make-up of an organism (or the alleles that they have) is known as the genotype.

The observable appearance of a trait in an organism as a result of the genes.

He established principles of inheritance based on research in pea plants.

Gene pairs separate when gametes form.

During meiosis, it is random which chromosomes line up on either side of the metaphase plate during metaphase I. This means that different combinations of DNA are made and that traits are inherited separately.

It is used to predict the possible outcomes of a genetic cross.

Breed an individual of unknown genotype, but dominant phenotype, with a homozygous recessive individual. Based on observation we can determine if it is homozygous dominant or heterozgous.

Controlled by genes located on autosomes.

Controlled by sex chromosomes.

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A rare bleeding disorder.

A pattern of inheritance in which two alleles in a heterozygote are partially expressed.

A pattern of inheritance in which both alleles in a heterozygote are fully expressed.

When there are 3 possible alleles but each person still only has 2 alleles (one on each homologous chromosome)

An individual which is most successful at reproducing.

A group of organisms that are capable of producing fertile offspring in nature.

A group of organisms of the same species living together and sharing/competing for resources.

Charles Darwin's theory of a mechanism for evolution, organisms with traits favorable to their environment are more likely to survive, reproduce, and pass on favorable traits to offspring.

Something that helps an individual to survive and reproduce.

This occurs when there are more individuals with the advantageous trait in the population; when they reproduce they pass such traits to offspring.

A process in which once-related populations evolve independently; often because they are geographically isolated.

The evolution of a new species. This occurs when two populations diverge so much that they can no longer reproduce with each other.

He found the natural selection theory and its five principles.

A French naturalist who began developing ideas about evolution.

Once a structure is modified by use or disuse, the modification is inherited by the organism's offspring. WRONG

Look at the transitional forms, which are fossils that show the changes and intermediate steps between the ancestor and modern form.

Comparing body structures.

Structures that share a common ancestry.

Structures that are reduced in size and function but suggest the historical form.

Stages of development of embryos look similar in all organisms.