Cell Reproduction and the Continuity of Life | Booklet 1

Unit 1 Booklet 1, Bio 3201

Somatic Cell

All cells of the body, excluding sex cells (Sperm and Egg cells)

46 Chromosomes

Ex. Nerve cells, liver cells, skin cells, etc.

Deoxyribonucleic Acid (DNA)

Inside the nucleus of the cell

Double stranded nucleic acid that determines our hereditary material.

Chromatin

uncondensed form of genetic material that predominates for most of the life cycle of the cell

Before becoming condensed

Chromosome

Condensed form of genetic material

Autosome

Chromosome other than sex chromosome

One of the two types of chromosomes

Sex Chromosome

X or Y; determines genetic sex

One of the two types of chromosomes

Cell Cycle

The life cycle of a cell

Does not end, unlike human life cycle.

A single cycle is defined as the sequence of events from one cell division to the next

Interphase

Growth stage of the cell cycle

Three phases:

G1 Phase

S Phase

G2 Phase

Cell division stage

Stage of the cell cycle, includes:

Mitosis

Cytokinesis

Cytokinesis

Separation of the cytoplasm and organelles to form two separate daughter cells

Sister Chromatid

One of two chromosomes that are genetically identical and held together at the centromere

Gene

Governs expression of a trait. Eg: Hair Color

Allele

One of the different forms of the same gene

Diploid

cell with two pairs of homologous chromosomes

Cleavage

Process of cell division without growth

Centrioles

Organelles that moves to opposite poles of the cell during phosphase of mitosis; Provides an attachment for the spindle apparatus

Spindle Fibers

Fibers that form the spindle apparatus during cell division (Mitosis)

Nuclear Membrane

A membrane that encloses the nucleus

Centromere

the point at which two sister chromatids of a chromosome are joined and to which the spindle fibers are attached during mitosis

Cell Plate

Only in plants

Structure across a dividing plant cell that signals the location of new plasma membranes and cell walls

Meiosis

Cell division that produces haploid gametes. it occurs in germ (sex) cells, which are found in the ovaries of females and testes of males

Germ cell

gamete producing cell

Meiosis II

Similar to the phases of mitosis

Four stages:

Phosphase II

Metaphase II

Anaphase II

Telophase II

At the end of this phase, four haploid daughter cells are produced, containing single, unreplicated chromosomes

Haploid

Cell with half the number of chromosomes as diploid (sex cells = 23 chromosomes)

Homologous chromosomes

Chromosomes with the same gene sequence

Non-sister chromatids

Chromosomes in a tetrad that do not belong to the same chromosome

Synapsis

Where alignment of homologous chromosomes occurs in phosphase I

Tetrad

Homologous chromosome pair; contains four chromatids

Gamete

Male or female reproductive cell

Spermatogonium

diploid germ cell

Polar body

After meiosis I, this cell has no cytoplasm and breaks down.

Sperm cell

male sex cell

Tail called flagella, used for movement

Middle piece contains mitochondria

head contains the nucleus and the acrosome

Acrosome produces enzymes used to penetrate the egg during fertilization

Egg cell

Female sex cell

Is non-motile (Can’t move by itself) but cilia inside the fallopian tubes help it to move to the uterus.

A mature (viable) egg cell is for the most part a large amount of cytoplasm and a nucleus

jelly coat produces proteins that help guide sperm to the egg

Cancer

Cell Mutation, permanent change to a cells DNA

Uncontrolled cell division

Oncogenes

Cells that can not be turned off and cause abnormal cell growth

What causes genetic change?

Heredity, UV radiation, viruses, toxins

Surgery

Cancer treatment

Removes the cancerous tumor

Radiation

X-Rays used on a localized area

Cancer treatment

Chemotherapy

Cancer treatment

Drug treatment program used to attack dividing cells which are spreading.

Asexual Reproduction

Reproduction that requires only one parent

Parent organism produces genetically identical offspring

Sexual Reproduction

reproduction that requires two parents

Involves the fertilization of gametes

Offspring are genetically unique

Plant Cells

Do NOT have centrioles

cell wall produces a cell plate

Animal cells

Have Centrioles

Cell membrane produces a cleavage furrow

Binary Fission

When a bacterial cell reproduces

Results in two identical daughter cells

Oogensis

Meiosis in females

occurs in the ovaries

process begins with a diploid germ cell called oogonium

Spermatogenesis

Meiosis in males

Occurs in the male testes

process begins with a diploid germ cell called a spermatogonium

Budding

a new organism develops from an outgrowth of the parent body

The new organism then seperates to become an independent organism

eg. Hydra

Vegatative Reproduction

a new plant grows from the growth of a modified stem, called stolons (runners)

eg. strawberries

Fragmentation

involves the development of a new species from a fragment (portion) of the parent species

eg. potato, sea stars

Parthenogenesis

An unfertilized egg develops into an adult

eg. Aphids, Honey Bees

Spores

a reproductive cell able to develop in to a new organism

small and readily dispersed by the wind

they are released by the parent body

eg. many species of fungi

Virus

not classified as a living organism

Cannot reproduce

lack cellular structure and metabolism

Lytic Cycle

Five step process where a virus invades and destroys a host cell

1. Attachment

2. Entry

3. Replication

4. Assembly

5. Lysis

Lysogenic Cycle

Like the Lytic cycle, but it enters the host cell sneakily, and only affects the host when it is aggravated

ex. Herpes/ cold sores and stress

Alternation of Generation

Is the concept that plants (and some animals) alternate between two generations:

haploid (n) generation

a diploid (2n) generation

Alternation of Generation in plants

The diploid(2n) generation is called the sporophyte generation

This generation produces haploid spores capable of growing into a plant body called gametophyte

THIS generation produces gametes which fertilize and develop into anothee sporophyte.

Cycle repeats

Fruit

The mature ovary

Seed

The mature ovule

Haploid (Plants)

In plants, the haploid (n) gametophyte produces the gametes, or sperm and egg, by mitosis

Diploid (Plants)

In plants, when sperm fertilizes the egg, it makes a diploid (2n) zygote

Double Fertilization

One sperm fertilizes the egg to form the 2n zygote, and the other sperm fertilizes the 2 polar nuclei to form the 3n endosperm

Triploid Endosperm

Tissue that surrounds and nourishes the embryo in the seeds of angiosperms (flowers). The food source.

-Made from 2 polar nuclei + 1 sperm

Embryo

Young developing plant

Polar Nuclei

the two nuclei of a seed plant embryo sac that are destined to form endosperm.

Ovule

Plant structure that develops into a seed when fertilized

Megaspores

the larger of the two types of spore produced by some spore-bearing plants, which develops into the female gametophyte

Gametophyte

The sexual phase (or an individual representing the phase )in the alternation of generations

Sporophyte

the diploid multicellular stage in the life cycle of a plant or alga

Double Fertilization

This occurs when..

1.One sperm fertilizes the egg forming the diploid zygote (2n)

2.The second sperm fertilizes the polar nuclei forming a triploid (3n) cell called endosperm - a starch food reserve for the embryo

After fertilization, the ovule develops into the seed, and the ovary develops into the fruit

begins when the generative nucleus produces 2 sperm. One of these sperm will go on to fertilize the egg, forming a diploid zygote (2n)

Pollination

When pollen lands on the stigma, this occurs

The tube nucleus forms a pollen tube and the generative nucleus forms two sperm cells

The pollen tube grows and penetrates the ovary, and ovule, releasing both sperm cells.

Pistil

Female reproductive organ (In plants)

Stigma

Part of the female reproductive organ

Sticky “lip” of the carpel that captures pollen grains

Style

Part of the female reproductive organ

stalk that supports the stigma

Ovary

Part of the female reproductive organ

Swollen base of the carpel that contains ovules

Ovules

Part of the female reproductive organ

Sac that contains female gametes

Petals

Colorful structures, attract pollinators

Sepals

surround and protect the flower bud

Stamen

Male reproductive organ (in plants)

Where pollination occurs

Anther

Part of the male reproductive organ

Where pollen is produced and stored

Pollen

Part of the male reproductive organ

case that contains male gametes

Filament Stalk

Part of the male reproductive organ

Supports the Anther