Science Chapter 4

Front 1

Cell division

Back 1

increases the number of cells and causes many-celled organisms to grow

Front 2

The Cell Cycle

Back 2

series of events that takes place from one cell division to the next

Front 3

Interphase

Back 3

most of the life of any eukaryotic cell, or cell with a nucleus, is spent in a period of growth and development, During interphase, a cell duplicates its chromosomes and prepares for cell division, After interphase, the nucleus divides, and then the cytoplasm separates to form two new cells

Front 4

Mitosis

Back 4

process in which the nucleus divides to form two identical nuclei

Front 5

Chromosome

Back 5

structure in the nucleus that contains hereditary material

Front 6

Prophase

Back 6

the first stage, Nucleolus and nuclear membrane disintegrate, Centrioles move to opposite ends of the cell, Spindle fibers begin to stretch across the cell

Front 7

Metaphase

Back 7

the second stage, pairs of chromatids line up across the center of the cell

Front 8

Anaphase

Back 8

the third stage, Each centromere divides, Each pair of chromatids separates and moves to opposite ends of the cell

Front 9

Telophase

Back 9

the fourth stage, spindle fibers disappear and a new nucleus forms

Front 10

Division of the Cytoplasm

Back 10

for most cells, the cytoplasm separates after the nucleus divides, In animal cells, the cell membrane pinches in the middle and the cytoplasm divides, In plant cells, a cell plate forms

Front 11

Results of mitosis

Back 11

Each cell in your body, except sex cells, has a nucleus with 46 chromosomes, Allows growth and replaces worn out or damaged cells

Front 12

Asexual reproduction

Back 12

a new organism is produced from one parent organism

Front 13

fission

Back 13

An organism with no nucleus divides into two identical organisms by fission

Front 14

Budding

Back 14

a small, exact copy of the adult grows from the body of the parent

Front 15

regeneration

Back 15

In regeneration, a whole new organism grows from each piece of the parent

Front 16

Sexual reproduction

Back 16

two sex cells, usually an egg and a sperm, come together

Front 17

Fertilization

Back 17

the joining of an egg and a sperm, generally from two different organisms of the same species, Following fertilization, cell division begins and a new organism develops

Front 18

reproductive organs

Back 18

Sperm are formed in the male reproductive organs, Eggs are formed in the female reproductive organs

Front 19

zygote

Back 19

A cell that forms from fertilization is a zygote

Front 20

human body cells

Back 20

Human body cells are diploid, because they have 23 pairs of similar chromosomes.

Front 21

human sex cells

Back 21

Human sex cells are haploid, because they have 23 single chromosomes

Front 22

Meiosis

Back 22

a process that produces haploid sex cells and ensures that offspring have the same diploid number as its parent

Front 23

meiosis 1

Back 23

In meiosis I, the nucleus divides and produces two new cells with one duplicated chromosome each

Front 24

meiosis 2

Back 24

In meiosis II, the nuclei divide and the chromatids separate, producing four cells with half the number of chromosomes of the original nucleus

Front 25

DNA

Back 25

a chemical that contains information that an organism needs to grow and function, Watson and Crick made an accurate model of DNA in 1953, The structure of DNA is similar to a twisted ladder, The sides of the ladder are made up of sugar-phosphate molecules, The rungs of the ladder are made up of nitrogen bases, Before a cell divides, its DNA duplicates itself by unwinding and separating its sides, then each side becomes a pattern on which a new side forms

Front 26

Genes

Back 26

sections of DNA on a chromosome, Contain instructions for making specific proteins

Front 27

RNA

Back 27

RNA carries the codes for making proteins from the nucleus to the ribosomes in the cytoplasm

Front 28

Messenger RNA (mRNA)

Back 28

carries the code that directs the order in which the amino acids bond

Front 29

Ribosomal RNA (rRNA)

Back 29

makes up ribosomes, where proteins are built

Front 30

Transfer RNA (tRNA)

Back 30

brings amino acids to the ribosomes to build the protein

Front 31

Mutations

Back 31

any permanent change in the DNA sequence of a cell’s gene or chromosome, . Can be caused by outside factors like X rays, sunlight, and some chemicals, A change in a gene or chromosome can change the traits of an organism

Front 32

types of nitrogen bases

Back 32

Adenine (A), Guanine (G), Cytosine (C), and Thymine (T).
A binds with T
G binds with C