Cell Anatomy and Division + Cell Permeability and Transport

What are cells?

The basic living units of tissue

What do cells do?

There are over 200 different cell types, and each specialized to perform essential functions

Why is the cell membrane semipermeable?

Enables the plasma membrane to surround and protect the cytoplasm while allowing the passage of certain materials in and out of the cell

What is semi permeable?

A barrier or membrane that allows some molecules to pass through while blocking larger particles (like proteins).

What are the different kinds of cells found in the human body?

Bone cells, blood cells, nerve cells, muscle cells, skin cells, and sex cells.

Plasma membrane

Is a flexible barrier that forms the outer layer of animal cells. It seperates the cells internal environment from its external environment.

phospholipid bilayer

A lipid bilayer, which is mostly composed of phospholipid molecules, but also contains smaller amounts of glycolipid and cholesterol molecules

Cytoplasm

The cytoplasm forms the inner contents of all cells, including animal cells. It contains all the contents between the nucleus and the plasma membrane.

Cytoskeleton

consists of proteins called microfilaments and microtubules that support the cell. The centrosomes containing centrioles and pericentriolar material that are essential for cell division.

Microtubules

grow outward toward the periphery of a cell. They are the thickest of the three types; have long, hollow shape; and are composed of protein tubulin. They determine the shape of a cell and contribute to the movement of organelles.

Microfilaments

provide strength, support, and motility for the cell. They are primarily composed of the protein actin.

Centrosome

Is an organelle in the cytoplasm of anima cells

Centrioles

are composed of clusteters of microtubules in a circular arrangement

Ribosomes

synthesize proteins. Some ribosomes float freely in the cytosol, while others are attached to cellular structures.

Rough endoplasmic reticulum

is a continuous with the outer nuclear membrane, and it gets its rough appearance from its numerous, protein-synthesizing ribosomes that are attached to it

Smooth endoplasmic reticulum

forms a network of tubules. It gets its name from the lack of lipids, hormones, and other cellular products, which are distributed throughout the cell by transport vesicles.

golgi complex

receives proteins, synthesized by ribosomes on the rough endoplasmic reticulum, via transport on the rough endoplasmic reticulum, via transport vesicles. It also processes and distributes lipids and complex carbonhydrates

Mitochondria

is a membrane-bound organelles located in the cytoplasm of eukaryotic cells, including both animal and plant cells

Lysososomes

are capsules inside the cell that contain digestive enzymes. Their function is to break down substances consumed by the cell or to recycle waste.

Peroxisomes

Are organelles in the cytoplasm of a cell. Also known as microbodies, they are smaller, but similar in structure to lysosomes. They contain oxidases, enzymes that oxidize organic substances.

Transport Vesicles

Some substances are transported to and from the pasma membrane in membranous sacs. This process expends energy, so it is a form of active transport.

Nucleus

The nucleus is a large organelle that contains the cell’s genetic information. Surrounded by cytoplasm, it is located in the center of the cell. Most cells have a single nucleus, but some have multiple nuclei, and other cells, such as mature red blood cells, do not have a nucleus at all.

Nuclear envelope

Is a double membrane, similar in structure to the plasma membrane, surrounds the nucleus, and opening sin the nuclear membrane called nuclear pores control the flow of substances in an out.

Nucleoplasm

A viscous liquid inside called nucleoplasm contains the contents of the nucleus

Nucleolus

One or more spherical bodies inside the nucleus that serve as the site of ribosomal RNA synthesis

Chromosomes

The cells genetic information is encoded in the DNA molecules, which arranged along chromosomes. Human somatic cells have 46 chromosomes, each of which contains long molecules of DNA coiled around proteins.

Why do cells have a membrane?

It serves as protection for the cell

How does the structure of the cell membrane makes it semipermeable?

Enables the plasma membrane to surround and protect the cytoplasm while allowing the passage of certain materials in and out of the cell.

What are the roles of proteins in the membrane?

Proteins are chains of amino acids that have many functions in the body, including acting as hormones in the endocrine system, contracting muscles, and transporting substances in the bloodstream and across cell membranes.

Diffusion

The passive movement of molecules from a higher to lower concentration until equilibrium is reaches

Osmosis

Is the passive movement of water from an area of high water (low solute) concentration to an area of a lowe water (high solute) concentration. While a limited amount of water molecules can move directly through the phospholipid bilayer, specialized protein channels called aquaporins facilitate the more rapid movement of water across the plasma membrane.

hypertonic solution

• Higher solute concentration

• Cells crenate

isotonic solution

• No net movement

• Water continues to cross the membrane

  • Always in motion

hypotonic solution

• Lower solute concentration

• Cell lyse

Ex: You have a beaker split down the middle by a semipermeable membrane. You fill both sides with water and then add salt to the right side but not to the left. Which way does the water move?Which way does the salt move?If the solutes cannot move what happens to the osmotic pressure?

• The water moves to the right side and the salt has no movement.

• The osmotic pressure increases because the water moves to balance the concentration gradient

What is the difference between facilitate diffusion and simple diffusion?

Simple diffusion: is the passive movement of small, nonpolar molecules such as oxygen - directly through the cell membrane down their concentration gradient

Facilitated diffusion - is the passive movement of molecules such as sodium across the plasma membrane down their concentration gradient.

What does the process of cellular respiration make from glucose?

Cellular respiration is a series of processes that take place within a cell to break down glucose to make ATP. The three main processes are glycolic, the citric acid cycle, and oxidative phosphorylation.

Transcribe

In transcription, DNA’s information is encoded or transcribe into RNA. For genes that code for proteins, the RNA is called messenger or mRNA. The process begins when RNA polymerase opens the double helix DNA, like slider on a zipper. It unwinds the DNA double helix and pries the two DNA strands apart

translation

Is the formation of a linear chain of amino acids, suing the transcribed information provided by an mRNA strand.

G1 phase (cell cycle)

• Cells grow larger 

• Carries out normal cellular function 

S phase (cell cycle)

• DNA is replicated 

• Sister chromatids are formed 

• Organelles increase in number 

G2 phase (cell cycle)

• Cells grow larger 

• Prepares to divide 

• Carries out normal cellular functions 

Interphase

G1, S phase, G2

mitosis

prophase, metaphase, anaphase, telophase

Prophase

• First stage

• Chromatin condense into visible chromosomes containing 2 identical sister chromatids

• Nuclear envelope begins to breakdown

• Spindle fibers begin to appear

Metaphase

• Second stage

• Chromosomes align along equator

• Nuclear envelope gone

• Centrioles migrate to opposite poles

• Mitotic spindles attack to centromere of each sister chromatid

Anaphase

• Third stage 

• Chromatids separated to produce individual chromosomes 

• Chromosomes migrate towards each pole 

Telophase

• Fourth stage 

• Chromosomes reach poles  

• Spindles begin to disappear 

• Nuclei begin to form 

• Plasma membrane begins to divide into 2 daughter cells 

Cytokinesis

• Cells have divided into 2 identical daughter cells 

• Each cell enters interphase