BIOSCI 107 - module 2

Lectures: 1

DNA in simple terms

heritable material

RNA in simple terms

Messenger

Proteins in simple terms

Workers

What does the cytoplasm include

everything in the cell except nucleus

what is Cytosol

The liquid component of the cytoplasm.

What is the cytoplasm made from

water + dissolved and suspended substances (ions, lipids, ATP, proteins)

What makes up the Endomembrane system

Nucleus, ER, Golgi, Vesicles

What is the Endomembrane system responsible for

Packaging, labelling and shipping molecules along with Plasma membrane

Cytoplasm function

Structural support, protection, storage, metabolic processes, transport

Function of Plasma Membrane

Cell signaling, structural support, protection, homeostasis, movement of molecules

What is the Plasma membrane

A selectively permeable outer layer of the cell made from a double phospholipid layer with embedded proteins

Phospholipid

Makes up plasma membrane, has hydrophobic lipid tails (fatty acid) and hydrophilic polar heads (phosphate)

What do fats in the cell membrane do

Provide a barrier to water

Which kind of protein is this

Integral, transmembrane protein

What kind of proteins are the arrows pointing to?

Periphereal membrane proteins

What is the green thing?

Glycolipid

Glycolipid function

Cell recognition

Function of PM proteins

mediate movement of hydrophillic substances

Plasma membrane proteins are often amphipathic, which means

have hydrophillic and hydrophobic regions

Integral proteins

Embedded in PM

Transmembrane proteins

Integral proteins that span the PM connecting extracellular and cytoplasmic areas

Periphereal membrane proteins

associated but not embedded in plasma membrane

Transport- channels, general or selective, gated or not

Enzymatic activity- chemical reaction, may be team of enzymes

Signal transduction- external signaling molecule causing communication to inside cell

Cell to cell recognition- use of glycoproteins as molecular signatures of extracellular side of cell

What is a glycoprotein made of

Carbohydrate and protein

Intercellular joining- junctions eg gap, tight

Attachment to cytoskeleton and ECM- eg, fibronectin mediates contact between cell surface integrins and ECM, facilitates movement

What is nucleus made from

A double bilayer (nuclear envelope) that is continuous with RER. Contains nucelolous and pores.

Nuclear pores

Control substances going in and out of nucleus

Nucleolous

Produces rRNA, assembly of small and large ribosomal. subunits

Functions of Nucleus

Make RNA, house and protect DNA, molecule segregation

What does molecule segregation in nucleus do

allows temporal and spatial control of cell function

Fill in green boxes

Histones, nucleosomes, chromatin fibres, centromere, sister chromatids

How many times doe the DNA wrap the histones

2

How many histones does the DNA wrap

8

Nucleosomes are made from

DNA wrapped 2x around 8 histones

Nucleosomes together form

chromatin

Chromatin forms

Chromatin fibers

What stage is DNA typically in inside a cell

Chromatin and Chromatin fibers

What do chromatin fibers form

chromosomes

Chromosome contains

usually more than 1000 genes

A gene is

segment of DNA that codes for a phenotype or function

What are ribosomes made of

Ribosomal RNA and proteins

rRNA meaning

ribosomal RNA

Where do ribosomal subunits assemble

in nucleolous, leave through nuclear pores

Where are Ribosomes found

Cytosol (non endo protein production), RER (endomembrane proteins production)

Function of RIbosomes

protein production (translation)

RER membrane surrounds protein to form transport vesicle to golgi

Proteins enter what part of RER and why

lumen for folding

function of RER

producing organelle, membrane and secreted proteins

SER has no ribosomes so it

doesnt make proteins

SER function

synthesizes lipids (steroids and phospholipids), storage of cell specific molecules

Examples of SER

muscle SER holds calciumm ions, Liver holds enzymes for detoxification and glucose release

golgi

Golgi

Cis face

side in golgi that receuves proteins from RER

Trans face

side of golgi where modified proteins are released

Function of golgi

modify, sort, package and transport proteins received from RER using enzymes in cisternae

Golgi forms

secretory vesicles (proteins for exocytosis), membrane vesicles (PM molecules), transport vesicles (molecules for lyosome)

Mitochondria

mitochondria

What is mitochondrias MAIN function

generation of ATP through cellular respiration

What is mitochondria made up of

Inner and outer mitochondrial membrane, mitochondrial matrix

Mitochondrial matrix

fluid filled interior cavity in mitochondria

Folds of inner mitochondrial membrane are

cristae

A cell has more mitochondria when

it uses lots of ATP, therefore needs to generate even more

Mitochondria carry seperate small

genomes (37 genes) encoding mithcondrial specific products

Name

Microvilli, microfilaments, intermediate filaments, microtubules

What does the cytoskeleton do

provides structural support to the cell, scaffolding, intercellular transport and cell movement

3 types of fibers in cytoskeleton from smallest to largest

microfilaments, intermediate filaments, microtubules

function of microfilaments

bear tension and weight by anchoring cytoskeleton to PM proteins, promote amoeboid motility

Where are microfilaments found

Periphery and lining of interior of cell

what do microfilaments look like

two long lengths of actin molecules twisted around eachother

How big are microfilaments

~7nm

Microfilaments assemble and dissasemble when required because they are

dynamic

How big are intermediate filaments

8-12nm

What are intermediate filaments made of

a wide range of materials eg keratin

Where are intermediate filaments found

cytoplasm

Function of intermediate filaments

Bear tension and weight throughout cell, scaffold for cellular organelles (nucleus)

Intermediate filaments are the most ____ of the fibers and are the least _____

permanent, dynamic

Intermediate filament

Microfilament

Microtubule

Structure of microtubules

Tubular, 25nm with 15nm central lumen

What are microtubules made from

Tubulin dimers coiled to form a tube

Functions of microtubules

support, road (moves organelles), chromosome organisation for cell division, support and movement of flagella/ cillia

Microtubules are

dynamic

What is a lysosome?

A lysosome is a membrane-bound organelle containing enzymes that break down waste materials and cellular debris.

ATP cycle

transfer of energy between complex and simple molecules in the body, with ATP mediator

pink

simple molecules (glucose, amino acids, fatty acids)

Green

Anabolic reactions transfer energy from ATP to complex molecules

Blue

Complex molecules (triglycerides, glycogen, proteins)

Orange

Catabolic reactions transfer energy from complex molecule to ATP

Major categories of fuel

Carbohydrates, Proteins, Fats

What are the three major fuels broken down into

Carbohydrates into simple sugars, protein into amino acids, fats into simple fats

What happens to fuel after being broken down

gets absorbed

The journey of glucose to cell

Glucose in food, glucose in bloodstream, facilitated by insulin becomes glucose in cell

Where does glucose go after being in cell

Cellular respiration or storage for harder times