Eukaryotic vs. Prokaryotic, Cell Specialization, Specialized Cells in Animals and Plants

prokaryotic

• do not have nucleus or organelles

• lacks membrane and bound nucleus and organelles

• genetic material is free in the cytoplasm

• ribosomes are only other cell structure

• found in single-celled organisms

eukaryotic

• have a nucleus and organelles

• mainly found in multicellular organisms

cell specialization

Process by which generic cells change to different types of cells to be able to perform special or specific functions

specialized cells in animals | RBC

Carry O_2­ throughout the body

• No nucleus (loses upon maturity to give more space to oxygen

• Biconcave shape (lubog ‘yung gitna; makes itself flexible)

• Contains hemoglobin (iron-rich protein which carries oxygen; gives blood the red color)

specialized cells in animals | WBC

Plays an important role in the immune system (protects us against illness and disease)

• Irregular shape (to pass through blood vessels)

• Can produce antibodies and antitoxins

specialized cells in animals | sperm cell

Fertilize an egg cell to make a baby

• Long tail (flagella) to swim

• Numerous mitochondria (as it takes a long time to meet with an egg cell; located in the neck portion)

• With chemicals on the head for egg cell entry

• Head contains the genetic material

specialized cells in animals | egg cell

Carries genetic material

• Large and bulky

• A chemical change in the membrane prevents fertilization of more than one sperm

specialized cells in animals | neuron (nerve cell)

Carry nerve impulses (signals) through the body

• Long, thin axon (sends)

• Branching dendrites (receive)

• Myelinated (for smoothening)

specialized cells in animals | muscle cell

Facilitate movement

• Elongated and elastic

• Numerous mitochondria

specialized cells in plants | guard cell

Regulates rate of transpiration

• Cell wall has varying thickness

• Can be found in stomata

• If it receives too much water, it swells (resulting into opening of stomata)

• If it loses water, it become straight (stomata closes)

specialized cells in plants | root hair cell

Absorbs water and minerals from the soil

• Long and thin with large surface area

specialized cells in plants | photosynthetic cells (mostly found in cells)

Produces food through the process of photosynthesis

• Contains numerous chloroplasts

specialized cells in plants | xylem vessel

Transport water and minerals from the roots to other parts of the plant

• Has lignin (molecule that makes the xylem vessel)

• No protoplasm (considered to be a dead cell once it matures)

• Cells form a continuous tube

cell modification

Adaptations or changes acquired by the cell after cell division that aids the cell in various beneficial ways

cell modification | cilia

Hair-like organelles extending from the cell surface

• E.g., lining of our respiratory tract, lining of fallopian tube, nose

cell modification | flagella

Long, whip-like, tail-like structures made of protein filaments

• Aids in movement

• E.g., sperm

cell modification | villi or microvilli

Small, slender, vascular, finger-like projections

• Increases surface area to increase absorption

• E.g., small intestines

cell modification | pseudopods (false feet)

Temporary extension of the cytoplasm

• Movement and ingestion (phagocytosis – big molecules)

• e.g., amoeba, WBC (engulfs invading molecules)

cell cycle

occurs as for growth and development of organisms, cell replacement, and for reproduction

• Driven by built-in clock that can be adjusted by external stimuli (i.e., chemical messages)

• series of events that occurs in a cell from one division to the next

• Generally divided into 2: interphase and mitotic phase 

interphase | gap 1

• Ensures the cell is large enough to divide, has enough nutrients to support resulting daughter cells

• Cell increase in size and volume

• Carbohydrates, lipids, proteins, and enzymes are produced in preparation for S and M phases

interphase | s phase

• Cell makes copies of all your genetic information (chromosomes)

• Amount of DNA has doubled (92 chromatids; 46 chromosomes)

• Only focuses on DNA replication

interphase | gap 2

• ensures that DNA replication in S phase has been successfully completed

• Helped by centrosomes (organize all of the stuff about to be divided between the cell and its soon-to-be replicant)

• Cell has everything it needs for division

interphase | gap 0

cell that is not preparing to divide

cell division

process by which cells reproduce

cell division | mitosis

Nuclear division; the process of nucleus division to produce two new nuclei

• Done most by your body cells

• Results to 2 daughter cells that are genetically identical to each other and to the parental cell from which they came

interphase

Occurs before mitosis; growth, DNA replication, carrying out cell functions

• Where cells spend most of their time

• 90%

• 46 chromosomes must be duplicated = 92 chromosomes before mitosis

mitosis | prophase

• Preparatory stage: centrioles move toward opposite sides of the nucleus

• Pro = before

• Mitotic spindle forms

mitosis | metaphase

Chromosomes become arranged so that their centromeres become aligned in one place, halfway between the two spindle poles

• chromosomes are in the middle

mitosis | anaphase

• Initiated by the separation of sister chromatids at their junction point at the centromere

• Daughter chromosomes then move toward the poles

• Moves away from each other

mitosis | telophase

Daughter chromosomes complete their migration to the poles

cytokinesis

division of cytoplasm, final separation

cancer

uncontrolled growth

chromosomes

made up of dna and protein

centromeres

attaches sister chromatids

• site for the attachment of spindle fiber

cell division | meiosis

• For sex cells

• Produces haploid gametes or spores with only one set of chromosomes

• During sexual production: gametes combine in fertilization to reconstitute the diploid complement found in parental cells

meiosis | first meiotic division

• Results in reducing the number of chromosomes (reduction division)

• Mostly accompanied by cytokinesis

1st meiotic division | prophase I

• spindles are starting to form, crossing-over

• before (where the chromosomes are going to condense and thicken and line up with their homologous pairs)

1st meiotic division | metaphase I

lining up in the middle (two pairs)

1st meiotic division | anaphase I

chromosomes are pulled away by the spindle fiber

1st meiotic division | telophase I

two newly formed nuclei’ has 2 new cells

second meiotic division | prophase II

spindles are starting to form like PI

second meiotic division | metaphase II

chromosomes line up in the middle but in a single file only

second meiotic division | anaphase II

chromatids are pulled away by the spindle fibers

second meiotic division | telophase II

4 haploid cells are formed

cell membrane

• A membrane made of two layers of phospholipids with embedded proteins that separates the insides of the cell from its environment

• Proteins, lipids (most abundant molecular component), cholesterol, carbohydrates