cell bio module 1

how are cells similar?

all cells have cell membrane, cell wall, cytoplasm, DNA, ribosomes, and an ability to perform energy metabolism

how are cells different?

prokaryotic cells lack a true nucleus and membrane-bound organelles, are generally smaller and simpler

eukaryotic cells have nucleus enclosing genetic material and different membrane-enclosed organelles, much larger and more complex

what do genes provide

provide instructions for them form, function, and the behavior of cells and organisms

what are prokaryotic cells divided into?

bacteria and archaea

eukaryotic cell

mitochondria generates usable energy from food molecules

chloroplasts use sunlight as energy

internal membranes create compartments that serve different functions

cytosol is a concentrated aqueous gel

cytoskeleton is responsible for cell movements

covalent vs. non covalent bonds

covalent bond- when atoms share electrons very strongly to make a stable connection, electrons are often shared unequally

non-covalent bond- weaker attraction between atoms or molecules, can be easily broken or reformed

what are the main atoms and small molecules in cells?

C, H, O, N

what are the macromolecules in cells?

nucleotides, DNA, amino acids, macromolecules, proteins

what is condensation reaction?

when two small molecules join together to make a bigger one and during this process a small water molecule is released

( imagine two lego bricks and a tiny piece pops up)

what is hydrolysis?

when a large molecule is broken down into smaller molecules by adding a water molecule

what can atoms do get a stable arrangement of electrons

by interacting with one another in the outermost shell

why are covalent bonds are important to make macromolecules in cells

covalent bonds are strong and stable which can allow atoms to share electrons tightly and form chains that make up macromolecules

strong links keep large molecules intact and functional within the cell

macromolecules in condensation reactions

where smaller molecules join together to form a larger macromolecule and a water molecule is released as a byproduct

macromolecules in hydrolysis

where a macromolecule is broken down into its smaller individual units by the addition of a water molecule

what chemical bonds bring molecules together

non-covalent bonds, electrostatic interactions, Van Der Waals attractions, hydrophobic forces, h-bonds

what is needed for a macromolecule assembly

both covalent adn non-covalent bonds

what are anabolic reactions

a process that builds complex molecules from simpler ones and requires an input of energy

is essential for growth and repair

what are catabolic reactions

processes that break down complex molecules into simpler ones and releasing energy

how are catabolic and anabolic reactions relate to free energy?

catabolic: exergonic, results in a net decrease in system’s free energy and the released energy can be collected by the cell for other processes

anabolic: endergonic, requires an input of energy, increase in the system’s free energy, is non-spontaneous

how is change in free energy relates to entropy?

by the Gibbs free energy formula

increase in entropy

negative deltaG, meaning theee is an increases spontaneity of a reaction at higher temperatures

decrease in entropy

positive deltaG, meaning there is no spontaneity of a reaction, releases heat

what do enzymes do in cells?

they speed up chemical reactions in cells without being used up themselves

like a tool that helps build or break specific molecules faster and efficiently

what is an activated carrier

a molecule that stores energy or an energetic group in a readily exchangeable form

condensation reactions and macromolecules

condensation reaction helps build macromolecules

hydrolysis and macromolecules

hydrolysis helps break down macromolecules into smaller ones

favorable vs. unfavorable reactions

favorable- releases energy and can happen with no energy input, these reactions give off energy that the cell can use

unfavorable- requires energy to occur

how do unfavurale reactions occur in cells?

reaction coupling and change in concentration

what is the structure of DNA

a double helix just like a twisted ladder, made up of two long strands of nucleotides

what is a chromosome

organized packages of DNA that make up your entire genome in a cell

what are the types of DNA damage?

chemical changes to bases, missing bases, breaks in the DNA backbone, cross-linking, replication errors

what happens when there is a chemical damage to bases in DNA

when the DNA strands get changed, which can lead to misreading by the cell

what happens when there is a missing base damage in DNA

when there is a gap in the DNA strand

what happens when there are breaks in the DNA backbone?

when the DNA strand itself can break

what happens when there is cross-linking DNA damage

when different parts on the DNA get stuck together abnormally which prevents them from being read or copied properly

what the replication error in DNA damage

a mistake that happens when DNA is being copied which leads to wrong bases being put in or small segments being left out or added

how can DNA damage cause mutations

• if a base is changed or missing then the cell’s machinery might insert the wrong partner base when replication is happening

• when there is a missing base or break in DNA strand, then the replication machine will skip it which can lead to a deletion or insertion of a base

• large scale arrangments

how is the DNA a heritable material in cells?

each time a cell divides to make new cells, it makes an exact copy to pass on to their offspring

how is DNA packaged into chromatin?

DNA wraps around histones to create nucleosomes, that then coil and stack into denser chromatin fibers which form domains that attach to a protein ladder

during cell division chromatin undergoes extreme condensation to form chromosomes to make sure the genetic material is preserved

what are nucleosomes

represent the first level of DNA packaging

bead like structure formed when a segment of DNA wraps around a core of histone proteins which helps condense DNA

acetylation

loosens chromatin

gene activation

methylation

depends on the site, can either activate or repress

gene regulation

H3K4me3- active transcription

H3K27me3 - gene silencing

phosphorylation

chromatin condensation

DNA repair

cell cycle, stress responce

what is a histone code?

a code that has a system of chemical modifications on histones that helps control what genes need to be on or off without changing the sequence itself

ex: some tags say “open up this part for gene activation” or “ keep this tightly packed for gene silencing”

what can help determine structure of chromatin

modification od histones

ATP depending chromatin remodeling

non-histone proteins

what is cell memory?

that is how a cell remembers where to go after it divides