Lecture A1, A2 Flashcards by Tami Ojewole

Only universal characteristics of human cells

-eukaryotic
-animal cell (not plant cell)

How well did you know this?

Not at all

Perfectly

Problem with textbook depictions of human cells

-has a collection of all the thing that can be in a cell but most cells don’t have all these characteristics

How well did you know this?

Not at all

Perfectly

Histology is the study of ______

-cells on slides

How well did you know this?

Not at all

Perfectly

Histology involves the ________

-preparation of tissue samples for study under a microscope

How well did you know this?

Not at all

Perfectly

Histochemistry is the study of _____

cells using biochemistry/chemistry

How well did you know this?

Not at all

Perfectly

Histochemistry involves the ______

the differential staining of cells based on chemical differences of the parts

How well did you know this?

Not at all

Perfectly

Cell stains are useful because ______

tissues are mostly transparent (cells are mostly made of water)

How well did you know this?

Not at all

Perfectly

Appearance of cells with cell stains are specific to ______

cell types

How well did you know this?

Not at all

Perfectly

Cell biology is the study of ______

cells, their inner structures and their interactions with the environment in which they exist

How well did you know this?

Not at all

Perfectly

Cell biology involves a number of scientific disciplines: ________ (4)

physics, biochemistry, physiology, and genetics

How well did you know this?

Not at all

Perfectly

4 Characteristics of human cells

-diverse
-change over time/ develop
-morphology reflects function
-all have the same set of genes despite morphological differences

How well did you know this?

Not at all

Perfectly

mass of average human cell

10^-12 - 10^-11

How well did you know this?

Not at all

Perfectly

number of cells in human body

10^13 to 10^14

How well did you know this?

Not at all

Perfectly

cells in human body are mostly ______

-red blood cells (84%), platelets (5%), bone marrow cells (2.5%)

How well did you know this?

Not at all

Perfectly

humans are mostly ______

blood and stuff that make up blood (platelets, bone marrow lymphocytes etc.)

How well did you know this?

Not at all

Perfectly

All human cells have the _____ but not all _______

-same genes
-genes are active in any given cell

How well did you know this?

Not at all

Perfectly

humans are a bad lab animal because ______

-hard to breed
-lie (hard to measure)
-very diverse

How well did you know this?

Not at all

Perfectly

humans are studied in the lab by ____

-taking human cells to study them

How well did you know this?

Not at all

Perfectly

Most human cell studies are performed _____

on isolated cells grown in plastic dishes

How well did you know this?

Not at all

Perfectly

HeLa cells characteristics

-can grow on plates
-more chromosomes in cell than regular 46
-transformed (cervical cancer cell)

How well did you know this?

Not at all

Perfectly

stage where humans cells are all identical

8 cell stage (all similar without differentiation)

How well did you know this?

Not at all

Perfectly

progression steps: zygote –> _____ –> ______ —-> ______

-morula
-blastula
-gastrula

How well did you know this?

Not at all

Perfectly

morula (def.)

solid mass of blastomeres from multiple cleavages of zygote

How well did you know this?

Not at all

Perfectly

blastula (def.)

hollow sphere of blastomeres with inner fluid filled cavity

How well did you know this?

Not at all

Perfectly

blastula (descr.)

-has inner blastocoel (inner fluid cavity) -has outer blastoderms (single layer embryonic epithelial tissue)

blastula grows and forms this next cell stage: ______

gastrula

gastrula is considered true human cells because the cells experience ______

cell differentiation

gastrula (def.)

early multicellular embryo, composed of 3 germinal layers of cells from which the various organs later derive.

gastrula 3 layers descriptions

-ectoderm (outer) -mesoderm (middle) -endoderm (inner)

blastopore is _______ (def.)

opening of the central cavity of gastrula

Gastrulation consists of ______

invagination of the blastomeres of one side of the blastula and cell differentiation leading to 3 layers

ectoderm forms ______ (3)

-outer surface (the skin cells of epidermis) -central nervous system (neurons) -neural crest (pigment cells - melanocytes)

mesoderm forms _____ (5)

-notochord -skeletal muscle cells -kidney cells -red blood cells -head (facial muscle)

endoderm forms ______ (3)

-digestive tube (ex. pancreatic cell) -pharynx (ex. thyroid cell) -respiratory cells (ex. lung cell)

What establish human cell diversity?

differences in gene expression

human cells are sorted into categories based on ______

their roles in the body

specialized cell for this activity: movement

muscle and other contractile cells

specialized cell for this activity: adhesive and tight junctions

epithelial cells

specialized cell for this activity: secrete parts of ECM

fibroblasts, cells of bone and cartilage

specialized cell for this activity: covert stimuli into action potentials

neurons and sensory cells

specialized cell for this activity: secrete degradative enzymes

digestive glands

specialized cell for this activity: secrete glycoproteins

mucous glands

specialized cell for this activity: secrete steroids

adrenal gland, testis and ovary

specialized cell for this activity: ion transport

kidney and salivary gland ducts

specialized cell for this activity: intracellular digestion

macrophages and neutrophils

specialized cell for this activity: lipid storage

fat cells

specialized cell for this activity: metabolite absorption

intestine cells

Cell differentiation depends on changes in _____ rather than on any changes in the _______

-gene expression -nucleotide sequence of the cell's genome

______ of a few key ______ drives cell differentiation.

-Combinatorial control -gene regulatory proteins (transcription factors)

There are ______ genes in the human genome (approximately)

21306

Number of unique cell types in human cells

200 unique cell types

Type of proteins produced by the cell (5)

-transcription factors -structural proteins -enzymes -signaling proteins -organelle proteins

Differences in _____ provide cells with its unique properties and functions

protein expression

asymmetric division (def.)

sister cells are born different due to asymmetric inheritance of cellular components (e.g. proteins, RNAs) during mitosis

symmetric division (def.)

sister cells are born the same (equal inheritance) but become different as result of influence acting on them after their birth

Genes are encoded in ____

DNA which is in the nucleus

Eukaryotic DNA is packaged into _____

chromatin

euchromatin (def.)

transcriptionally active genes which are packaged less tightly

heterochromatin (def.)

repressed genes which are packaged more tightly

Types of transcription factors

1) activators 2) repressors 3) other TF

activator proteins do what?

bind to pieces of DNA called enhancers which causes the DNA to bend, bringing the gene promotor close to the proteins

other TFs + activator proteins = _____

protein complex that binds to gene promoter

the complex formed by activator proteins and other TF makes it ______

easier for RNA polymerase to attach to promoter and start transcribing

transcriptional memory means that ______

once a cell becomes a type of cell, it has to stay that type of cell

TFs are _____ (def.)

multi-protein complexes that are assembled on the DNA

TFs function (def.)

-can enhance or repress transcription from a gene

Function of TF changes depending on _____

the various proteins present

TF that you should know + (most -> least)

-ZNF-C2H2 – Zinc Finger (most) -HLH - Helix-Loop-Helix (or Homeodomain (Homeobox)) -bZIP - Basic Leucine Zipper -ZNF-GATA - Zinc finger protein that binds GATA (least)

Human TF genes are located where?

-in cluster within our chromosomes

TFs that bind to activate genes that specify hepatocyte (liver) cell (5)

-HNF1 -HNF3 -HNF4 -C/EBP -AP1

HNF1 (def.)

hepatocyte-specific homeobox

HNF3 (def.)

hepatocyte-specific bHLH

HNF4 (def.) + expressed where?

-nuclear receptor that also is expressed in intestinal epithelial cells and kidney tubule cells

C/EBP (def.) + expressed where?

a bZip that also is expressed in intestinal epithelial cells, fat cells, and some neurons

AP1 (def.) + expressed where?

a small family of bZip proteins that are expressed in virtually all cell types

Potential (def.)

Cells with greater ‘potential’ can divide and differentiate into a greater number of different types of cells

Specification (def.)

Cells have achieved a final fate

during development, human cells become more _____ and lose _____ in terms of their cell fate

-specific -potential

Short term genetic memory of changes in gene transcription involves ______

TFs that regulate their own genes (increasing their production)

Short term genetic memory is lost during ______ because _____

-DNA replication (S-phase) -TFs are removed as DNA is unwound and copied

Long term genetic memory is _____

epigenetics

Epigenetics involves ______ through _____ or ________

-heritable changes in chromatin that are not encoded in the DNA -changes in chromatin structure by methylation -by binding proteins to chromatin that block access to TFs and RNA polymerase

changes in chromatin structure regulate access to ______

coactivators/repressors and other TFs

Type of Histone Modifications

-methylation -acetylation -phosphorylation

Type of DNA Modifications (base level)

DNA base methylation (ex. cytosine)

DNA methylation is re-established by regulatory proteins ________ during the ______

-demethylases (remove)/ methyl transferase (add) -cell cycle

long term epigenetic memory of gene activation/repression proteins are ______

maintained through the cell cycle

proteins that block access to TF and RNA polymerase II by binding to chromatin often recognize ____

methylated DNA bases

methylation of histone amino-terminal tail = _____

heterochromatin (condensed)

acetylation of histone amino-terminal tail = _____

euchromatin (relaxed)

number of TFs that create human cell diversity

510

Most TF in human body are _____ and some are _____

-tissue specific -ubiquitous : expressed in different cell types