Week 3 Cell function, Growth, and Development

cell (plasma) membrane

boundary between cell and its environment, flexible, made up of lipid bilayer, selectively permeable

Cell wall

only in plants, boundary outside cell membrane, rigid, protects from turger pressure, gives shape to cell, composed of cellulose

Nucleus

manages cell function

Nuclear membrane

nuclear pores allow for materials to pass between nucleus and rest of cell

Nucleoplasm

liquid like substance in nucleus contains genetic material

Nucleolus

production of ribosomes

Cytoplasm

Fluid inside the cell that surrounds organelles, free ribosomes found here

Endoplasmic reticulum

Folded system of membrane which provide a large surface area for chemical reactions to take place

Smooth ER

no ribosomes, lipid synthesis

Rough ER

attached ribosomes, protein synthesis

Golgi apparatus

stacked, flattened, membrane sacs, receives assembled proteins and lipids from ER and distributes them in vesicles to plasma membrane or cell parts

when ribosomes are involved what are we talking about?

protein synthesis

Vacuole

fluid sac used for storage of materials, stores food, enzymes, and other materials. (large in plant, small and numerous in animal)

Ribosomes

site of protein synthesis, found in cytoplasm and attached to rough ER

Lysosomes

contains digestive enzymes, digests worn-out cell parts, fights invading bacteria and viruses, the membrane surrounding it prevents it from destroying itself, first immune system defense

mitochondria

food molecules broken down to release energy, has an inner membrane (cristae)

Chloroplasts

transforms light into glucose (a usable form), contains chlorophyll which helps trap light energy, is green

cytoskeleton

composed of tiny rods and filaments that form framework of cell, provides support for organelles

Centrioles

only in animal cells, helps form spindle fibers which aid during mitosis and meiosis (cell division)

Cilia

short, hair like projections, occur in large numbers, wave like movement, used for locomotion (animals)

Flagella

long, tail like projection, one or two per cell, whip like movement, used for locomotion (animals)

luecoplasts

found in roots and seeds, colorless, not exposed to light

chromoplasts

found in petals, and fruit, carotene, xanthophyll

chloroplasts

found in leaves, chlorophyll

Plastids

plant organelle used for storage, named according to pigments

Cell Growth

Depends on the use of genetic information in DNA to make the structural and functional proteins needed for cell survival​

Cell reproduction

Ensures that genetic information is passed from one generation to the next​

Anabolism

Protein synthesis is a central anabolic pathway in cells

Deoxyribonucleic acid (DNA)​

A double-helix polymer (composed of nucleotides) that functions to transfer information, encoded in genes, to direct the synthesis of proteins

Gene

A segment of a DNA molecule that consists of approximately 1000 pairs of nucleotides and contains the code for synthesizing one RNA molecule, which then may be translated into one polypeptide

Coding RNA

mRNA, which is a transcript of a code for one polypeptide​

Noncoding RNA

rRNA and tRNA, which are copies of a DNA gene but regulate processes rather than code for a polypeptide ​

Transcription

mRNA forms along a segment of one strand of DNA

Editing the transcript

Noncoding introns are removed and the remaining exons are kept and spliced together to form the final, edited version of the mRNA copy of the DNA segment​

Spliceosomes

Ribosome-sized structures in the nucleus that splice mRNA transcripts

RNA polymerase

In the nucleus, makes an RNA copy of the DNA (gene)

Messenger RNA (mRNA)

Contains both introns and exons

Spliceosomes

Remove the introns and keep the exons  (editing)​

Edited mRNA

Is transported out of the nucleus​

Translation of mRNA

Transfer to a protein occurs in the cytoplasm​

Cell growth

A newly formed cell produces a variety of molecules and other structures necessary for  growth by using the information contained in the genes of DNA molecules; this stage is known as  interphase​

Production of cytoplasm

More cell material is made, including growth and/or replication of organelles and plasma membrane; a largely anabolic process

DNA replication

Replication of the genome prepares the cell for reproduction; the mechanics are similar to RNA synthesis

DNA base paring

The DNA strand un-coils and the strands come apart​

Along each separate strand a complementary strand forms​

The two new strands are called chromatids instead of chromosomes​

Chromatids are attached pairs, and the centromere is the name of their point of attachment ​

Growth phase

The cell life cycle can be subdivided into the first growth phase (G1), the DNA synthesis phase (S), and the second growth phase (G2)​

Cell reproduction

Cells reproduce by splitting themselves into two smaller daughter cells

Mitotic cell division

The process of organizing and distributing nuclear DNA during cell division has four distinct phases

Prophase (“before phase”)​

After the cell has prepared for reproduction during interphase, the nuclear envelope falls apart as the chromatids coil up to form chromosomes joined at the centromere ​

As chromosomes form, the centriole pairs move toward the poles of the parent cell and spindle fibers are constructed between them

Metaphase (“position-changing phase”)

Chromosomes move so that one chromatid of each chromosome faces its respective pole​

Each chromatid attaches to a spindle fiber​

Anaphase (“apart phase”)​

The centromere of each chromosome has split to form two chromosomes, each consisting of a single DNA molecule​

Each chromosome is pulled toward the nearest pole to form two separate but identical pools of genetic information​

Telophase (“end phase”)

DNA returns to its original form and location within the cell​

After completion of telophase, each daughter cell begins interphase to develop into a mature cell​

Meiosis I

reduction division 2N  1N)​

Meiosis II

Mitosis of Haploid cells four 1N (haploid NOT IDENTICAL)​