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If you're here, it's probably because you're looking for a little (or a lot!) more help with biology. I can do that!

Take a look around - I think you'll find some great stuff here...and if you're looking for more personalized help, check out the online tutoring options. Let's do some biology!

Meet Your Other Bio Professor

Hi, I'm Sarah!

I have an undergraduate degree in biology, a PhD in genetics, and several years of experience teaching college biology. As your other biology professor, I'm using what I learned as both a student and a teacher of biology to help you avoid getting lost in the details. When I'm not doing bio things, I'm probably traveling, hiking, or sewing up a new outfit.

Think we might be a match made in bio heaven?

Not sure yet? Follow me on social media for more biology lessons and study tools!

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Biology Mini-lessons

Ready to learn some bio? Check out my channel on YouTube - new videos coming soon!

I make the kinds of videos that I struggled to find for my own students. There's a lot of great content out there, but much of it feels geared towards kids or med school prep...and we really need something in between! In my videos, we review concepts, highlight common points of confusion, run through memory tips and tricks, and do a little practice to make sure everything is clear. Designed largely for the introductory undergraduate crowd, but also totally appropriate for many high school/secondary classes, and as review for more advanced courses.

Wobble [with Inosine, Codon bias, and Anticodons that don't exist!]

Wobble [with Inosine, Codon bias, and Anticodons that don't exist!]

Are you asking yourself, "how does base-pairing wobble during translation?" I got you! "Wobble" is all about how the codon-anticodon pairing rules get extra-flexible at one particular base. This allows for an anticodon to bind with multiple codons for the same amino acid, so the cell doesn't have to make as many different types of tRNAs. At the wobble site, we can have... 1. Normal base-pairing (A-U, G-C) 2. G-U pairing 3. Inosine in the anticodon pairing with A, C, or U in the codon 00:00 Intro 00:25 Codon table 01:36 Stop codons bind release factors, not anticodons! 01:59 Why don't we need 61 different types of tRNAs for 61 different codons? 03:02 Redundancy of the genetic code; synonymous codons 05:15 The wobble position 06:21 Expanded base-pairing rules at the wobble position 08:07 Inosine in the anticodon pairs with A, C, or U in the codon 09:54 Codon usage bias 11:04 Some anticodons aren't produced 14:07 Review *NOTES* You'll often see the word "degenerate" used to describe how a single amino acid can be encoded by more than one codon - same idea as "redundant" here. :) "Inosine" is actually the name of the nucleoside that contains our modified base AND a pentose sugar (like how an adenine base and a pentose sugar = the nucleoside "adenosine"). The name of the base in inosine is "hypoxanthine," but unless your class has a heavy biochemistry component, you're not likely to find this referred to as anything but inosine in the context of wobble. *Connect with me!* Website: Instagram: *References* Codon usage bias data found at:
17 Essential Genetics Terms: a concept map! (AP, IB, Intro Biology)

17 Essential Genetics Terms: a concept map! (AP, IB, Intro Biology)

Let's connect the dots on some of the most-often mixed-up genetics terms, including... Chromosome vs chromatin vs chromatid Locus vs gene vs allele Genotype vs phenotype ...and more! Tutoring information AND a blank version of this concept map (for practice!): 00:00 Preview 00:57 GENOME vs CHROMOSOME 01:13 Prokaryotic vs. eukaryotic chromosomes 01:36 AUTOSOME vs SEX CHROMOSOME 02:17 CHROMATIN 03:08 CENTROMERE 03:46 CHROMATID (REPLICATED CHROMOSOMES and SISTER CHROMATIDS) 04:37 LOCUS (and loci) 05:03 GENE 05:30 ALLELE 05:44 GENOTYPE 06:08 HOMOZYGOUS, HETEROZYGOUS, and HOMOZYGOUS 06:45 PHENOTYPE 07:11 Genetics vocabulary concept map New videos are always on the way - subscribe so you don't miss any of my biology tips :) Connect with me! Tutoring information: Instagram: RELATED VIDEOS: *Homologous chromosomes: *Cell Division: *Replicated chromosomes: *Ploidy: *Dominant/Recessive alleles: The GENOME is the complete set of genetic material in a particular organism or cell - all of the DNA for that organism or cell. And the genome is stored in CHROMOSOMES. Each chromosome is a single molecule of DNA. Now, in prokaryotes like bacteria, chromosomes are circular whereas in eukaryotes like you and me, chromosomes are linear, meaning they have ends. In eukaryotic organisms like humans, proteins help to package the chromosomes, help to keep the DNA nice and dense and packaged up so it fits in the nucleus. This is also helpful for controlling when genes are transcribed. We call this combination this mixture of DNA and protein CHROMATIN. When you look at a eukaryotic chromosome you'll notice an area that is a little more tightly packed, kind of pinched-in. This is called the CENTROMERE, and despite the name it's not always in the center of the chromosome. The centromere is a region of very repetitive DNA sequences. This tightly packed chromatin acts sort of like an attachment point, it's going to be very important for attachment during cell division, allowing for other proteins to guide the chromosomes where they need to go in the cell. DNA replication changes the shape of the chromosome so instead of our stick-like structures, now we'll have x-shaped chromosomes - replicated chromosomes that consist of two molecules of DNA. Each half of our replicated chromosome consists of one DNA molecule and is called a CHROMATID. These are attached to each other at the centromere. (We love attaching things at the centromere.) Because the two chromatids on a single replicated chromosome are identical, we were refer to them as SISTER CHROMATIDS. So when you see "LOCUS," think "location." That's really what a locus is, it's the physical location on a chromosome of some DNA sequence of interest. At a particular locus we could find a GENE. Genes are passed from parent to offspring, they often code for proteins, and they contribute to your physical and physiological characteristics. ALLELES are different versions, different sequences for a particular gene. Different alleles produce different gene products, which can impact an organism in different ways. The GENOTYPE tells us which combination of alleles is present for a particular gene or DNA region of interest. If the two alleles are the same (you inherited the same gene sequence from your mother as from your father), we would describe the genotype as HOMOZYGOUS. If they're different we would describe that genotype as HETEROZYGOUS. Okay, well... what if you can't have two alleles? An individual who is XY for example can only have one copy of the alleles on the X chromosome - we would describe this as HEMIZYGOUS. The PHENOTYPE is how we observe an individual's traits (physical, physiological, behavioral) as determined by their genetic makeup (the genotype) as well as environmental impacts.
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